To see their updates really, but I follow those I'm friends with. However, it's hard to go through and choose a friend from your list if you want because that's not possible. You have to look through pages and pages to find a specific person and it's easier to just go to "profiles" then type their screenname. But people follow just to sort of friend each other. Oh shit, actually most people probably do it because you get like one point to follow someone, so that is one reason for the excessive amount of following that happens.