You can tell that Twitter has added something important to the ecosystem by the volume of the snickering. If you dismiss it by asking "Why do I care what you had for breakfast?", there are only two choices. First, you're saying everyone on Twitter is an idiot. Second, you don't understand what you're talking about. As a Twitterer (dweinberger), I'm going to go with Option #2.
Twitter's success tells us a lot...including the following 4.5 points:
1. Twitter in its native form assumes we're ok with not keeping up with the abundance. Tweets are going to scroll by when you're not looking, and you're never going to see them. Twitter assumes you will let them go, the way most of us cannot leave messages in our email inboxes unread (or undismissed).
2. Social asymmetry addresses the scaling problem. At Twitter, the people you follow are not necessarily the people who are following you. That's exactly not how mailing lists and weekly status meetings work, and Twitter's approach impedes the back-and-forth development of ideas. But, maybe that's not what Twitter is primarily about. And the asymmetry means that some people can have lots of followers but still participate as listeners.
2.5. (Maybe in an age of abundance, the back and forth development of ideas isn't the only process. Sure, having a small group kick around an idea often works. But maybe in some instances it also works for an idea to be lobbed like a beach ball from one group to another, each putting their own spin on it.)
3. Twitter is an app that scales as as platform. That is, it comes with a set of features that makes it usable and popular. But it's open enough to enable users and third parties to add capabilities that make it useful for what it wasn't designed for. For example, a convention has arisen among users that "RT" will stand for "re-tweet" when you want to publish someone else's tweet to one's own followers.
4. We'll complicate simple things as much as we have to. We'll invent "hashtags" (tags that begin with #, embedded within a tweet) to let people find tweets on a particular topic, getting past the "it already scrolled past" issue. We'll invent layers upon layers of aggregators of tweets. We'll just bang away on it as hard as we have to in order to accrete significance. We truly are meaning monkeys.