Two questions that we get every week (literally) from our customers are:
1) How did this post get on my Facebook wall?
2) I have a friend who says they are getting messages from me - but I know I didn't send it and I have a strong password - how did this happen?
I ran across this article in USA Today this week and it sums up how these two incidents happen. More often than not it's driven from the fact that the user clicked a link....that they thought was from a friend. Oftentimes these links are very exciting or enticing and they prey upon your instinct to click before you think.