We all know the debate - LinkedIn is professional but not very functional. Facebook is really functional but totally unprofessional (how many sheep have you thrown today?)
Andy Steggles even references this in his vodcast about using the new ASAE membership directory:
But Guy Kawasaki rides to the rescue with 10 Ways to Use LinkedIn. And this was written before LinkedIn added the questions and groups functions, which means there are now TWELVE ways to use LinkedIn!