It took 4 weeks but it did reach $15 and then it very quickly dropped back to $8... So after all, I am good at this prediction thingy... Can one put limit orders on this thing? I see it is traded on different websites. Are those connected (I see different prices) or does a bitcoin trader have to set up account with each one?
Yeah. You can get an account with Mt Gox. They are basically "the game" as far as execution goes in the US. There was another popular exchange, Bitfloor, which recently was hacked for $200,000+ IIRC If you plan on trading large amounts of bitcoin I would recommend a Yubikey, which is a small security device that unlocks your account. There are too many convenient hacks in the BTC world, if you plan on keeping coins for yourself on the side to dollar cost average KEEP THEM IN YOUR OWN PERSONAL WALLET and don't leave them with anyone else. Fair warning, lol. I would take a look at www.bitcointalk.org, which is the forums for all things bitcoin. EDIT: About the real trading price / different websites. That is where a lot of arb takes place and I would imagine it is being done all day by a variety of people. There are posts on that forum I linked which go into detail about that same subject. Basically, a bitcoin is a bitcoin is a bitcoin. But anyway, yes, you would have to setup multiple accounts with all your various small other exchanges.
kronos.io (search) I believe allows margin trading / shorting, but I am not sure. Used to be able to do it with bitcoinica.... I am sure there is another major service like this in the works.
people are doing this right now, more or less an arb situation between different exchanges, but the liquidity isn't really there for true HFT. Right now maybe about $16,000 USD of liquidity within 10 cents of the best bid and ask on both sides.. take a look for yourself at bitcoin.clarkmoody.com