What this thread is about
This is a thread where I (and possibly others) talk about myself. Given my level of activity in this forum I believe creating such a thread is justified. It can serve a variety of purposes:
1. Informing people I have a business dealing with about my track record, reputation and commitment to Bitcoin.
2. Informing people who may seek my advice about my skills and experience.
3. Satisfying the curiosity of anyone who is interested in knowing more about me.
4. Posting updates about myself that could be relevant to people with a stake in my various projects.
5. Giving customers/partners a place to report any misconduct on my part (and, through lack of such reports, demonstrate my trustworthiness to those who would come here to look).
A bit about me, personally
I was born in 1984 in Haifa, Israel, and have since moved to Hadera and then to Tel Aviv. I served in the IDF as an artillery battalion's telecommunications platoon sergeant, and then proceeded to complete an M.Sc. in mathematics from the Weizmann Institute of Science, doing a machine learning thesis under the supervision of Boaz Nadler. After that (in 2009) I started working as the head of research of the internet startup SimilarWeb, a position from which I started to phase out once I've heard about Bitcoin.
Some of my online profiles include:
http://www.facebook.com/meni.rosenfeld
http://www.linkedin.com/profile/view?id=99439111
http://en.wikipedia.org/wiki/User:Meni_Rosenfeld
I am fairly selective about connecting on social networks, so most of my connections would be people I know in person and which could give a reference.
I first heard about Bitcoin in March 2011 from this LessWrong post talking about SIAI (now MIRI) accepting Bitcoin donations. I have since become increasingly more involved with it, and starting August 2011 I have focused entirely on Bitcoin endeavors.
Bitcoin, Israel and myself
My largest area of activity is with the promotion of Bitcoin in Israel. I currently serve as the chairman of the Israeli Bitcoin Association.
In April 2011 I have started a test run of Bitcoil (thread), a service for exchanging bitcoins for ILS in Israel, and it was officially launched in August 2011. For two years it has been the best method for people in Israel to buy or sell small to medium amounts of bitcoins, with many satisfied customers and demand reaching millions of ILS per month in early 2013. Unfortunately, the service is currently unavailable due to opposition by Israeli banks.
I am the founder and organizer of the Israel Bitcoin Meetup Group, hosting regular events almost weekly. These have evolved from 3 people meeting at a cafe to lecture-filled events with 180 attendees, as well as two full-blown conferences (one local and one international, and counting).
I am a co-founder and the main content contributor of the content site http://www.bitcoin.org.il/, and an admin of the Facebook page and IRC channel.
I have written Hebrew translations of bitcoin-qt and of Satoshi's whitepaper.
I'm giving talks and interviews to any interested parties, including Oracle, Payoneer, the Haifa Linux Club and the channel 10 program "Layla Calcali".
Mining pool reward methods
In March 2011 I have developed the geometric method, the first non-PPS hopping-proof reward method. It is the basis for the double geometric method (DGM) which I developed in August 2011. DGM greatly expands the range of options offered by the geometric method on the reward method triangle (making it practical to have low variance for both the miners and the pool operator), and currently enjoys some popularity with the mining pools.
In July 2011 I started working on the comprehensive guide to the subject, Analysis of Bitcoin Pooled Mining Reward Systems (thread), and finished in November 2011. I have also written a summary of the results.
GLBSE
Despite its many deficiencies, GLBSE was a very powerful platform while it lasted, and it is unfortunate what happened to it. I have made several issues on GLBSE:
PureMining: My first (and most successful) issue, and the first perpetual deterministic mining bond. The idea was devised when I was looking for a way to harness economies of scale in purchasing BFL FPGA equipment, and followed the issues that could arise to their logical conclusion. While many are still confused about the concept, I believe and hope it marks the way for how most mining investments and hedging will work in the future.
A total of 15566 bonds worth 1 MH/s each we issued. After the GLBSE shutdown, payment has proceeded for a while with a static list, until I bought the bonds back according to their contract.
Anti-Pirate: At a time when pirateat40's Bitcoin Savings and Trust was gaining popularity, and a rising trend was pass-throughs for investment, I offered the opposite - a way to short his operation. It was a perpetual asset designed so that the profit from it is exactly (up to fee and time value of money) the negative of an equivalent investment with Pirate, so that if one believed investment in Pirate is lossy, investment in Anti-Pirate would be profitable. For whatever reason, not a single bond was bought.
ABSORB: After Bitcoinica shut down, I and others were looking for a way to control our BTC position. ABSORB was an attempt to use GLBSE's trading functionality to emulate BTC/USD margin trading. It worked as a prediction market for which of two exchange rates, high and low, would be achieved first. This allowed placing a leveraged bet on increase or decrease of the exchange rate, with a calculable equivalent effect on the position. The first (and only) series was concluded with a 400 BTC payout.
POLY: An improved attempt to emulate margin trading, POLY worked by having a face value calculated as a power function of the current BTC/USD exchange rate. It allowed easier control of the position with a persistent asset. The bonds were eventually bought back for a total of 560 BTC.
The ugly
Through lifes bad times we appreciate the good.
I unfortunately agreed to help one Alberto Armandi to raise funds for Bitdaytrade, a margin trading platform he was working on, through the BDT bonds on GLBSE. It didn't work out so well. The story is not over yet, but due to either malice or incompetence of Alberto, he now has a debt of about 10K BTC which he seems unable or unwilling to repay.
I have learnt important lessons from the experience about both human nature and my own limitations.
Miscellaneous
I devised one proposal for a Proof of Stake system, and led the effort to get DOSBox to accept Bitcoin donations. I am now collaborating in the development of colored coins, and I have helped Adi Shamir with his research on the Bitcoin transaction graph. I have written an analysis of hashrate-based double-spending.
In my blog http://fieryspinningsword.com/ I write about a variety of things, mostly related directly or indirectly to Bitcoin.
People from the forum I've met
If you've been to any of the conferences in New York (2011), Prague (2011), London (2012), San Jose (2013), Amsterdam (2013) or Amsterdam (May 2014), you probably saw me.
In particular I recall talking with bearbones, jared@bitmunchies, MemoryDealers, matsh, btcx, Bruce Wagner, BitPay Business Solutions, Steve, jed, Stefan Thomas, Littleshop, nanotube, Jered Kenna (TradeHill), Gavin Andresen, coblee; FreeTrade, worldly, Pieter Wuille, slush, molecular, genjix, lonelyminer (Peter urda), Goonie; Inaba, ribuck, garyrowe, Vladimir, Mihai Alisie, Vandroiy, Nefario, jgarzik, jim618, mintymark, shtylman, Mike Hearn, Andrew Miller, kangasbros; aantonop, evoorhees, Yago, retep, etotheipi, enmaku, Yankee (BitInstant), maaku, JoelKatz, eMansipater, edd, Luke-Jr, gmaxwell, Rassah, crazy_rabbit, fellowtraveler, casascius; gigavps, adam3us and Vitalik Buterin.
Additionally, I have met in Israel ripper234, iddo, eyal, Andrew Vorobyov, Eli, gilgil, yoniassia, WiW and yona.
Bitcoin online communities
I am very active in the Bitcoin forum; my post count is evidence of that, but by itself it shows no indication of the quality of the posts. My posts can be sampled by picking pages randomly and reading the first post in each. (Reading through the posts in one page is not a proper sampling method; I could be having a good or bad day.)
I also have accounts on bitcoin.stackexchange, the Bitcoin wiki and the bitcoin-otc WoT.
Some of the threads I've started on the forum are:
Pledge for DOSBox donations (96 BTC sent)
Geometric method: New cheat-proof mining pool scoring method
A short note about variance and pool payouts
Bitcoil - Exchange bitcoins for ILS
Do we want oblivious mining pool shares?
Mining pool reward math FAQ
NodeBank - Concept for a p2p banking network
Analysis of Bitcoin Pooled Mining Reward Systems
Double geometric method: Hopping-proof, low-variance reward system
PPLNS
Israel Bitcoin Meetup Group
Using mixing transactions to improve anonymity
The mining pool reward method triangle
Outsourcing vanity address generation
[GLBSE] PureMining: Infinite-term, deterministic mining bond
Introduction to Bitcoin - from bitcoin.org.il
Israel Bitcoin community homepage
Bitcoin-qt unwanted translations
[GLBSE] (discontinued) Anti-Pirate: Bonds for negative BTCST investments
Mine in multiple pools to reduce variance
[IDEA] Casascius physical Bitrings
I've finally figured out BFL's name and logo
Why you should care about miners
Dynamic block frequency
Rollover transaction fees
Output upkeep costs
[GLBSE] ABSORB - Emulating BTC/USD margin trading
[WTB] [FILLED] 1000 BTC Contract for difference (I'm taking the short position)
[GLBSE] POLY - Persistent BTC/USD margin trading emulation
Trustless, instant, off-the-chain Bitcoin payments
[GLBSE] BDT - 3% weekly interest bond, backed by Bitdaytrade
Bitcoin icon on TV (City of London)
Unofficial attendance list - Bitcoin London 2012
Unofficial Bitdaytrade deposit claims thread
How to determine common ownership of addresses? (Inspired by Shamir's paper)
How to determine dormant coins? (Inspired by Shamir's paper)
Short presentation about Bitcoin (technical focus)
Salient block countdown timer
How to detect the change output?
The Jewish holidays thread
Analysis of hashrate-based double-spending
Getting Wikipedia to accept Bitcoin donations - Community pledge
Some presentations about Bitcoin
Multi-PPS
Meni's Blog - Fiery Spinning Sword
Bitcoin Israel Think Tank
Bitcoin in Israeli prime time TV - "The Magazine", November 2013
Israel Bitcoin Conference October 19-20, 2014
Crypto for the Masses - Israeli Bitcoin documentary film
O Bitcoinis - That's the first line of a poem I've written
Political views
I am not a libertarian, and I find many of the views expressed by people in the Bitcoin community to range from silly to appalling.
A few words about trust
One goal of this thread is to carry across the idea that I stake my real identity on everything that I do; I only have one of those and thus my reputation is of the utmost importance to me. This doesn't mean that I will now start asking to be trusted with large sums of money, or that you should comply if I do. The trick which allowed me to honor every obligation I've made is that I never promised more than I am able to keep. When taking new liabilities one needs to understand the risks of what he is offering and limit his exposure to allow a wide margin of error, even at the cost of missed profit opportunities; and counterparties need to make sure the person is so diligent. Personally I don't intend to enter liabilities of more than a few thousand BTC any time soon, and even that only if it is for a very good reason.
Edit: Oh, the good times when the thought of thousands of BTC in liabilities was on the table
I do however now have faithfully completed obligations up to the $700K range on my track record, and the reputation I've built in ~3 years is worth at least that.
Assets and liabilities
A complete breakdown of assets is more personal than I am comfortable sharing at this point. I will simply state that I currently have no liabilities.
This is a thread where I (and possibly others) talk about myself. Given my level of activity in this forum I believe creating such a thread is justified. It can serve a variety of purposes:
1. Informing people I have a business dealing with about my track record, reputation and commitment to Bitcoin.
2. Informing people who may seek my advice about my skills and experience.
3. Satisfying the curiosity of anyone who is interested in knowing more about me.
4. Posting updates about myself that could be relevant to people with a stake in my various projects.
5. Giving customers/partners a place to report any misconduct on my part (and, through lack of such reports, demonstrate my trustworthiness to those who would come here to look).
A bit about me, personally
I was born in 1984 in Haifa, Israel, and have since moved to Hadera and then to Tel Aviv. I served in the IDF as an artillery battalion's telecommunications platoon sergeant, and then proceeded to complete an M.Sc. in mathematics from the Weizmann Institute of Science, doing a machine learning thesis under the supervision of Boaz Nadler. After that (in 2009) I started working as the head of research of the internet startup SimilarWeb, a position from which I started to phase out once I've heard about Bitcoin.
Some of my online profiles include:
http://www.facebook.com/meni.rosenfeld
http://www.linkedin.com/profile/view?id=99439111
http://en.wikipedia.org/wiki/User:Meni_Rosenfeld
I am fairly selective about connecting on social networks, so most of my connections would be people I know in person and which could give a reference.
I first heard about Bitcoin in March 2011 from this LessWrong post talking about SIAI (now MIRI) accepting Bitcoin donations. I have since become increasingly more involved with it, and starting August 2011 I have focused entirely on Bitcoin endeavors.
Bitcoin, Israel and myself
My largest area of activity is with the promotion of Bitcoin in Israel. I currently serve as the chairman of the Israeli Bitcoin Association.
In April 2011 I have started a test run of Bitcoil (thread), a service for exchanging bitcoins for ILS in Israel, and it was officially launched in August 2011. For two years it has been the best method for people in Israel to buy or sell small to medium amounts of bitcoins, with many satisfied customers and demand reaching millions of ILS per month in early 2013. Unfortunately, the service is currently unavailable due to opposition by Israeli banks.
I am the founder and organizer of the Israel Bitcoin Meetup Group, hosting regular events almost weekly. These have evolved from 3 people meeting at a cafe to lecture-filled events with 180 attendees, as well as two full-blown conferences (one local and one international, and counting).
I am a co-founder and the main content contributor of the content site http://www.bitcoin.org.il/, and an admin of the Facebook page and IRC channel.
I have written Hebrew translations of bitcoin-qt and of Satoshi's whitepaper.
I'm giving talks and interviews to any interested parties, including Oracle, Payoneer, the Haifa Linux Club and the channel 10 program "Layla Calcali".
Mining pool reward methods
In March 2011 I have developed the geometric method, the first non-PPS hopping-proof reward method. It is the basis for the double geometric method (DGM) which I developed in August 2011. DGM greatly expands the range of options offered by the geometric method on the reward method triangle (making it practical to have low variance for both the miners and the pool operator), and currently enjoys some popularity with the mining pools.
In July 2011 I started working on the comprehensive guide to the subject, Analysis of Bitcoin Pooled Mining Reward Systems (thread), and finished in November 2011. I have also written a summary of the results.
GLBSE
Despite its many deficiencies, GLBSE was a very powerful platform while it lasted, and it is unfortunate what happened to it. I have made several issues on GLBSE:
PureMining: My first (and most successful) issue, and the first perpetual deterministic mining bond. The idea was devised when I was looking for a way to harness economies of scale in purchasing BFL FPGA equipment, and followed the issues that could arise to their logical conclusion. While many are still confused about the concept, I believe and hope it marks the way for how most mining investments and hedging will work in the future.
A total of 15566 bonds worth 1 MH/s each we issued. After the GLBSE shutdown, payment has proceeded for a while with a static list, until I bought the bonds back according to their contract.
Anti-Pirate: At a time when pirateat40's Bitcoin Savings and Trust was gaining popularity, and a rising trend was pass-throughs for investment, I offered the opposite - a way to short his operation. It was a perpetual asset designed so that the profit from it is exactly (up to fee and time value of money) the negative of an equivalent investment with Pirate, so that if one believed investment in Pirate is lossy, investment in Anti-Pirate would be profitable. For whatever reason, not a single bond was bought.
ABSORB: After Bitcoinica shut down, I and others were looking for a way to control our BTC position. ABSORB was an attempt to use GLBSE's trading functionality to emulate BTC/USD margin trading. It worked as a prediction market for which of two exchange rates, high and low, would be achieved first. This allowed placing a leveraged bet on increase or decrease of the exchange rate, with a calculable equivalent effect on the position. The first (and only) series was concluded with a 400 BTC payout.
POLY: An improved attempt to emulate margin trading, POLY worked by having a face value calculated as a power function of the current BTC/USD exchange rate. It allowed easier control of the position with a persistent asset. The bonds were eventually bought back for a total of 560 BTC.
The ugly
Through lifes bad times we appreciate the good.
I unfortunately agreed to help one Alberto Armandi to raise funds for Bitdaytrade, a margin trading platform he was working on, through the BDT bonds on GLBSE. It didn't work out so well. The story is not over yet, but due to either malice or incompetence of Alberto, he now has a debt of about 10K BTC which he seems unable or unwilling to repay.
I have learnt important lessons from the experience about both human nature and my own limitations.
Miscellaneous
I devised one proposal for a Proof of Stake system, and led the effort to get DOSBox to accept Bitcoin donations. I am now collaborating in the development of colored coins, and I have helped Adi Shamir with his research on the Bitcoin transaction graph. I have written an analysis of hashrate-based double-spending.
In my blog http://fieryspinningsword.com/ I write about a variety of things, mostly related directly or indirectly to Bitcoin.
People from the forum I've met
If you've been to any of the conferences in New York (2011), Prague (2011), London (2012), San Jose (2013), Amsterdam (2013) or Amsterdam (May 2014), you probably saw me.
In particular I recall talking with bearbones, jared@bitmunchies, MemoryDealers, matsh, btcx, Bruce Wagner, BitPay Business Solutions, Steve, jed, Stefan Thomas, Littleshop, nanotube, Jered Kenna (TradeHill), Gavin Andresen, coblee; FreeTrade, worldly, Pieter Wuille, slush, molecular, genjix, lonelyminer (Peter urda), Goonie; Inaba, ribuck, garyrowe, Vladimir, Mihai Alisie, Vandroiy, Nefario, jgarzik, jim618, mintymark, shtylman, Mike Hearn, Andrew Miller, kangasbros; aantonop, evoorhees, Yago, retep, etotheipi, enmaku, Yankee (BitInstant), maaku, JoelKatz, eMansipater, edd, Luke-Jr, gmaxwell, Rassah, crazy_rabbit, fellowtraveler, casascius; gigavps, adam3us and Vitalik Buterin.
Additionally, I have met in Israel ripper234, iddo, eyal, Andrew Vorobyov, Eli, gilgil, yoniassia, WiW and yona.
Bitcoin online communities
I am very active in the Bitcoin forum; my post count is evidence of that, but by itself it shows no indication of the quality of the posts. My posts can be sampled by picking pages randomly and reading the first post in each. (Reading through the posts in one page is not a proper sampling method; I could be having a good or bad day.)
I also have accounts on bitcoin.stackexchange, the Bitcoin wiki and the bitcoin-otc WoT.
Some of the threads I've started on the forum are:
Pledge for DOSBox donations (96 BTC sent)
Geometric method: New cheat-proof mining pool scoring method
A short note about variance and pool payouts
Bitcoil - Exchange bitcoins for ILS
Do we want oblivious mining pool shares?
Mining pool reward math FAQ
NodeBank - Concept for a p2p banking network
Analysis of Bitcoin Pooled Mining Reward Systems
Double geometric method: Hopping-proof, low-variance reward system
PPLNS
Israel Bitcoin Meetup Group
Using mixing transactions to improve anonymity
The mining pool reward method triangle
Outsourcing vanity address generation
[GLBSE] PureMining: Infinite-term, deterministic mining bond
Introduction to Bitcoin - from bitcoin.org.il
Israel Bitcoin community homepage
Bitcoin-qt unwanted translations
[GLBSE] (discontinued) Anti-Pirate: Bonds for negative BTCST investments
Mine in multiple pools to reduce variance
[IDEA] Casascius physical Bitrings
I've finally figured out BFL's name and logo
Why you should care about miners
Dynamic block frequency
Rollover transaction fees
Output upkeep costs
[GLBSE] ABSORB - Emulating BTC/USD margin trading
[WTB] [FILLED] 1000 BTC Contract for difference (I'm taking the short position)
[GLBSE] POLY - Persistent BTC/USD margin trading emulation
Trustless, instant, off-the-chain Bitcoin payments
[GLBSE] BDT - 3% weekly interest bond, backed by Bitdaytrade
Bitcoin icon on TV (City of London)
Unofficial attendance list - Bitcoin London 2012
Unofficial Bitdaytrade deposit claims thread
How to determine common ownership of addresses? (Inspired by Shamir's paper)
How to determine dormant coins? (Inspired by Shamir's paper)
Short presentation about Bitcoin (technical focus)
Salient block countdown timer
How to detect the change output?
The Jewish holidays thread
Analysis of hashrate-based double-spending
Getting Wikipedia to accept Bitcoin donations - Community pledge
Some presentations about Bitcoin
Multi-PPS
Meni's Blog - Fiery Spinning Sword
Bitcoin Israel Think Tank
Bitcoin in Israeli prime time TV - "The Magazine", November 2013
Israel Bitcoin Conference October 19-20, 2014
Crypto for the Masses - Israeli Bitcoin documentary film
O Bitcoinis - That's the first line of a poem I've written
Political views
I am not a libertarian, and I find many of the views expressed by people in the Bitcoin community to range from silly to appalling.
A few words about trust
One goal of this thread is to carry across the idea that I stake my real identity on everything that I do; I only have one of those and thus my reputation is of the utmost importance to me. This doesn't mean that I will now start asking to be trusted with large sums of money, or that you should comply if I do. The trick which allowed me to honor every obligation I've made is that I never promised more than I am able to keep. When taking new liabilities one needs to understand the risks of what he is offering and limit his exposure to allow a wide margin of error, even at the cost of missed profit opportunities; and counterparties need to make sure the person is so diligent. Personally I don't intend to enter liabilities of more than a few thousand BTC any time soon, and even that only if it is for a very good reason.
Edit: Oh, the good times when the thought of thousands of BTC in liabilities was on the table
I do however now have faithfully completed obligations up to the $700K range on my track record, and the reputation I've built in ~3 years is worth at least that.
Assets and liabilities
A complete breakdown of assets is more personal than I am comfortable sharing at this point. I will simply state that I currently have no liabilities.