Social Networking can either be a time consuming waste in chasing quantity over quality or a valuable opportunity to make connections that turn into relationships that convert into real sales. While it is true the larger your follower base, the greater your opportunity for making those connections, but it is also true that target networking is more valuable than blind networking.
4) Who Unfollowed Me? - This site allows you to see who unfollowed you and identifies a list of people are not following you back. (http://who.unfollowed.me)