One thing I have found aggravating about interacting with people on Facebook is that my interaction shows up in my social contacts' feeds.

This is fine if you have one community of friends, but gets weird if you have multiple, and downright bothersome if you want to keep them separate. In particular, I have a friend from middle school who will occasionally jump into a conversation that I enter with something unhelpful, and I cringe at the thought of someone else discovering that I'm the only mutual friend my LW friend has with my middle school friend. One solution, of course, is to unfriend everyone on FB I know who isn't a LWer. I find this unsatisfactory for many reasons. ;)