Malcolm Gladwell wrote a book called "The Tipping Point" a few years ago in which he hypothesized that there is a crucial level of interest that must be reached for a social phenomenon to take off. He argued that when a phenomenon does reach the critical point - the "tipping point" - interest didn't just gradually climb - it exploded. Imagine an unbalanced bucket of water, a drop adding at a time until suddenly it tips and spills its contents - it's an all or nothing kind of experience.

It looks like Twitter hit it's tipping point around February of 2009 (see graphic above).  

More factoids about Twitter and an interesting analysis are available here.

I've said this before - there is nothing special about Twitter's technology, so they are very vulnerable to other technologies that allow the same thing. But I'm starting to wonder about that. How I use Twitter is different than how most other addicts use Twitter.   I'm a news junky - I "follow" about 50 other Twitterers - but almost all of them are magazines, newspapers, or special interest organizations. I like Twitter because I can get a rapid-fire update of news from a wide variety of sources. But from what I can see - a lot of people actually value the Twitter interaction with personal followers. And there are people with literally thousands of followers. There is even a term for people with more than 10,000 followers - they're called "Whales". The motivation to be a whale is the idea that your little tweets potentially get read by thousands of other people. One doesn't become a whale by accident - unless one is already famous for something else. From what I can see, non-celebrity whales work very hard to be interesting to a broad audience, and part of that effort includes responding to their follower's tweets. In an environment where your followers can un-follow you with the click of a button, if a whale wants to hold on to his/her following, he has to feed his followers interesting content constantly. I mention whales to make the point that there is a percent of the Twitter population that is locked in to the service. It would be easy for me to jump to another service - I could reconstruct my feed easily. A whale would lose an enormous investment. This is the only way that Twitter can lock users in - to make it hard to reconstruct their account on a different company's service. Now the question is, how to get more people locked in - maybe not whales, but dolphins.
(HT to Michael Nielson for the link to Tech Crunch)