Since I have a new account and can only post here, here goes.
I have wallet on blockchain.info.
Last night I switched to an Android phone, and installed the Blockchain.info client. I have not used any cell phone bitcoin clients in the past.
This morning, my phone beeped with a notification for a transaction of -0.0005 bitcoins. I hadn't authorized any payments, and thought this was odd. Soon the transaction was confirmed - my account was drained! The transaction is here:
https://blockchain.info/tx/ad688e21be30e00e01a9417a9ad0201f7e54e496f4d85896991064895ab21971I find it beyond coincidental that this transaction occurred just hours after installing their client on my phone - it is my only related activity to this wallet in months. Even if it was, it may call into question the security of their system. Sure there are other possibilities (maybe someone hacked my home network) but this sure seems the most likely.
I realize that tracing this down is next to impossible, but I am posting this as a warning to other blockchain.info users. Their system or components of it may be compromised.
And no, I did not have 2 factor authentication enabled. Lesson learned. It would have stopped this from happening.