I personally have had the hardest time downloading facebook applications.  There is something about that screen that pops up that says it is going to have to “access my information” that makes me real nervous.  This is a great article on three of the major points: first off what are applications?, what do they have access to?, and can you control the activity.  I can honestly say after reading this article and learning that you can control your applications more with a newly installed app install screen, I feel a little more comfortable.