"Following" on Twitter, Friendfeed, "Friending" on Facebook, and "Connecting" on Linkedin are acts of respect, and generally greeted with appreciation as long as one is not a spammer, stalker or gross.
So why is there a set of Twitterers who believe having a high follower/following ratio is a status symbol?
Be like Barack... it's easy to use a tool like SocialToo to reciprocate following those who follow you. And it is an act of good will.
Yes, one can argue that "they only have the bandwidth to follow 120 or so", but by 120 followers, one needs a Tweet filtering system that would work just as well following 1,000's.
What's more confounding is having vendors with whom you buy products and services (or potentially can) unfollow you. It's an act of exclusion that alienates clients. Warning to any vendor on Twitter - don't unfollow, they may be your client.
Soon, most Twitterers will see that the act of unfollowing makes no sense. It's the filtering that makes monitoring Twitter efficient, and those you wouldn't normally follow won't make it through the filter.
The attitude shift towards mutual inclusion and following will make Twitter a far-reaching viral marketing platform as strangers in the nth degree of separation become interwoven within networks. Yes, there will always be those who use Twitter to connect on a partitioned level, as in an industry, and they will thrive. But Twitter will become mainstream when the masses see Twitter as a network or broadcast application and less like a chat box.