I think it is not so simple. Despite of the casual nature of Twitter, there is still a lot of diplomacy and politics involved. To me it still feels like the polite thing to do to follow back if somebody follows me - it is like answering "hello" if somebody says "hello" to you. Except that I completely stopped managing my Twitter followers atm, because it became too overwhelming.<p>Another example is #FollowFriday - how do you react if somebody recommends you? Recommend them back? Does recommending somebody mean you value your other followers less? And so on - just saying that there are still some issues...<p>Another issue is that if you are a company and want people to be able to contact you via Twitter, you basically have to auto-follow. People can only send you DMs if you follow them, after all. So if the following-limits become a problem, I could see auto-unfollow help, too.