Biggest pet peeve with LinkedIn: recruiters constantly trying to "friend" me.  Seriously, connecting is only for people who know each other.  I don't mind recruiters sending me all the email they want (sure I want to ditch my permanent job in the place I love to come work for your startup in South Dakota on a 3 month contract…), but stop trying to "friend" me!  We've never met, ergo we cannot possibly be friends at this moment in time. #EndRant