Hello, I have any questions
If I want to invest in bitcoin, what do you think this is useful for me or not? give me your opinions.
why I must invest in bitcoin? or why not? just give me strong reason.

I'd keep a look out for CombiCoin, now in ICO.

For every 10 dollars you invest, you get 1 CombiCoin, as well as 1 TRIA token.
Each CombiCoin represents 1/30th of the top 30 cryptocurrencies. The team have run a lot of simulations, and this turned out to be the ideal ratio:  in the first half of this year for example, BTC grew 194%, whereas the top 30 grew 1198%. They will do bi-monthly rebalancing to keep alts from becoming dominant within CombiCoin, and to be able to introduce successful newcomers.
This means that as long as the crypto market as a whole grows (which it has done, exponentially, for a long time now), the CombiCoins grow in proportion. You pay zero commission over this growth.

This is where the TRIA tokens come in. Specially designed software, which has been successfully applied in the energy sector, will keep track of all buying and selling orders of CombiCoins on as many exchanges as possible. Whenever these can be traded at a favorable rate, the smart software executes an order and generates profit. This profit is divided 50/50 between Triaconta - this is their business model - and the other half goes to the TRIA token holders. In other words, the token holders are basically guaranteed a steady income, as long as CombiCoins are being traded (which, in a growing crypto market with the coins rising in value, they will be).

I've already invested €1500 (about 2000 dollars), here's why:

- With all recent China related FUD, I think a lot of demand has risen for more stable (and no less considerable) profit. The market consists of more than moonkids and speculators;

- I find it hard to figure out which crypto's to hedge my bets on. There's a couple of relatively stable big ones, but with low profits, and the newcomers, which turn out to be one day flies a little too often for my taste. I do however have great faith in the rise of cryptocurrencies in general; in the crypto market as a whole. I firmly believe this market will grow at least tenfold in 2018, which would mean my 1.500 euro's will be 15.000 by the end of next year;

- This is not counting the revenue from the TRIA tokens. You get these basically for free during the ICO, and there's no telling how much each token will generate over a lifetime;

- The team consists of professors and other experienced professionals. The software they will implement has been tried and tested. They are very transparent and answer all questions on this forum and in their telegram quickly and thoroughly. I've asked many questions myself, but haven't been able to find a single unconsidered circumstance or any fatal flaw. They seem to have thought of everything. Only thing is that, where other (less promising) coins like Paragon are all in your face, CombiCoin is pretty low key and rather focuses on quality. This means it's partly up to the community to get the word out, but personally I'm glad to do it.

I'd say do your own research and check out their whitepaper on https://triaconta.com/

Mine are: Ethereum, Litecoin, Ripple, OmiseGo, Lisk, Golem, Augur, Lunyr, District0x, Bancor, 0x, Factom, Civic, Aragon, AdEx, and DigixDao.

What cryptos do you hold when the market is going down, and which you dump?

All are dead and no more new coins and which ever have started now they have to dilute their funds or else they are going to face a law problems.

OmiseGo (OMG) started their Airdrop campaign for ETH holders. 

I'm curious to know what do you think about these type of campaigns.

Are you immediately selling these tokens?

Are you likely to buy more?

Are you holding for future gains?

You do have a point there, mate. Bitcoin will always be the most prominent cryptocurrency on the markets, since it is the original cryptocurrency which brought us the blockchain technology. Without it, many of the cryptocurrencies we know and love today wouldn't have been possible. Considering that BCH is just a fork from the original Bitcoin blockchain, it may never replace it, the same way ETC never replaced the original Ethereum.

Therefore, I believe that in the future both of these cryptocurrencies will co-exist (Bitcoin and Bitcoin Cash) providing people with options whenever they want to quickly send a transaction or just secure their investments for the long term. Whenever it is Gold (BTC) or Cash (BCH), there will always be a choice for anyone to transact in this rapidly evolving technology. Just my thoughts

70 Billion? thats a far fetch statement. I hope you're right, would love to buy some cheap coins but I don't see it going under 100 Billion.

I follow OMG during this frop i cannot believe how strong it is. It has nearly stayed same price overalls. Yes it dropped iike 7.5-8 but that eqs such a short timeI wouldnt even coint. And now it recovers faster than ETC NEO and IOTA I expect to continue this really up with the september news

Bitcoin will always recover and in fact it's already recovering.
That the price went as low as $3000 doesn't mean that BTC is dying out. That's the volatility of these digital currencies.
Bitcoin cash can't overthrow bitcoins. Bitcoin is already very popular and widely accepted than Bitcoin cash.

What you Think About Opus Coin? Decentralized Music platform.  Now Its Price 0.02 $.  How much will rise in 2 month. and maybe it have good chance to add in bittrex.

What's your opinion, will Ethereum reach $1000 some day?

Hey, did anyone notice BCH volumes on Korean Bithumb (its about $300 mil as of time of this writing and rising)? Its gonna move Ripple soon and make it into top 3 on coinmarketcap if this continues. What are these guys are up to? Should we expect BCH rise due to Korean volumes?

I invested about 1btc in sia at a few diffrent times when it was between 300-450sat. As you know now its hovering around 100sat. So what is the best move here? Should I invest another bitcoin in sia now when its low? Or should I just leave it and hope some day it will go back up to atleast my initial investment?

I'm sure there are others who invested in sia when it was high as well. So whats your plans?