In this list you can find some interesting links that will make you doubt about your data security. Too many people thinks that give their own data to big corp means that they be protected. Actually is a big lie.
Here you can find a lot of (often very fresh) database of users. What does it mean? That if your data were stolen due to some attacks, everyone can see your username, passoword and e-mail.
A very full list of leaked databases.