Quote from: jorgebuck on April 29, 2013, 06:25:26 PM

That's just your bitcoin wallet address (found when you click receive coins). When received by the other party it will show up as sent by that number. He is just asking you to copy and paste it again in the thread so he can keep better track of it.

This is not necessarily true. It depends on what wallet program you are using (Electrum, MultiBit, Bitcoin-Qt, Armory, https://blockchain.info/wallet ) each has its own way of dealing with addresses and transactions.

Your advice is quite likely to be incorrect for some people using the Bitcoin-Qt wallet. The Bitcoin-Qt wallet moves some of your bitcoins to a brand new address that it doesn't tell you about every time you create a transaction. If you create a transaction that only uses the bitcoins at one of these brand new "change" addresses, then the address that they appear to be coming from won't be anywhere in the "Receive coins" section of your wallet.