You also want to be very careful about joining causes, or playing the app games on Facebook. When you click, a dialogue box comes up, and read the print...if you click 'yes', you authorize them access to your profile, pics, movies, and your friends' too. Here's what comes up first, check this out:
We can't display this content while you're viewing Facebook over a secure connection (https).
Would you like to temporarily switch to a regular connection (http) to use this app?
You will have a secure connection upon your next login.
Think about this...why would they want to use a non-secure connection? So they can get to your stuff!
Think first, protect your personal identification, and that of your friends...and always read the fine print.