The big pitfall in social networking be it twitter, facebook or another site, is the incessant spam and spambots which are not only annoying, but time consuming to detect and delete. While I cannot help with other sites, with Twitter the solution is Twerpspam.com. Bookmark it.
List and sort your followers and friends, up to 100 at a time. Follow, unfollow or block contacts right on the spot — either one by one, or many at once. And get a more complete picture about any Twitter user by using their handy Drilldown feature. [Hat tip to @TraderJon]