Rough idea:
COPY(my_address, my_priv_key, copied_address)
From this moment onward, every operation done by copied_address is copied by my address, in proportion to our funds. Meaning if copied_address holds X MSC and my_address holds Y MSC, and copied_address now places a market offer to sell Z MSC, then my_address will sell Z*Y/X MSC.
This of course needs more details to account for multiple currencies and assets stored on the same address.
https://trello.com/c/MX0ZymMD/20-soec-for-events-feedsJust thought I would post a little explanation about this feature.
Example:
Alice has 1000 MSC.
Bob has 100 MSC. Bob thinks Alice is a smart trader, and tells the decentralized Mastercoin system to just copy Alice.
Now, Alice sells 100 MSC using a market order. Immediately after this, Bob will automatically sell 10 MSC (10% of Alice's action). Let's assume for 1 BTC = 10 MSC
So now: Alice has 900 MSC and 10 BTC
Bob has 90 MSC and 1 BTC
Note that Bob was in vacation in Thailand and wasn't near his computer.
Now, let's say 1 BTC is worth 20 MSC, and Alice thinks it's a great buying opportunity. She spends 2 BTC to buy 40 MSC. Bob automatically copies this purchase.
Alice has now 940 MSC, and 8 BTC
Bob has 94 MSC and 0.8 BTC
Of course, in real life there is slippage. Bob will always get a slightly worse deal than Alice.