For about a week, I have not looked at my main bitcoin wallet. Then today, I opened my Bitcoin-QT wallet and saw that someone had sent me .0001 bitcoin.
That was rather surprising, since I have not done any trades or business using the addresses I have in that wallet. What I did find is that the fractional bitcoin was sent to the main address I use on my Twitter feed, and which I use to identify myself on bitcoin-otc.com and on the freenode IRC bitcoin channels.
So, I checked with blockchain.info and discovered that someone with a set of unusual vanity addresses had sent .0001 bitcoin to just about everyone who had labelled their address on Blockchain.
Take a look! Here is the blockchain entry for my main address https://blockchain.info/address/1EttqaSSCksRAXrwejoChs5zmGjSikN9mC
That fractional bitcoin came from
Whoever owns those unusual addresses seems to have made many small gifts.
If you know why this person did that, or if you are the owner of those unusual addresses, thanks!