How safe is to give your personal information on websites such as facebook, my space and any others? What’s the limit for you?

I think social networks are very useful, but are not always a safe site due to poor security. In many cases, it hasn’t been regularized the risk that others can use your data for some unknown reasons. In my opinion, the limit of personal information that should be shared on the network is only the general information, such as studies, hobbies or interests, and never reveal private details of your life or others close to you.