Twitter Activity Slowing Down - Whats Causing the Buzz Kill?

Twitter growth appears to be slowing. Even with cable news, reality TV personalities, and internet and social media marketers all widely embracing Twitter, the diffusion beyond this core set of supporters, at least compared to the historical adoption curves of MySpace, Facebook, and YouTube, appears to have hit a buzz kill.
The Sysomos study on Twitter usage, in the beginning of summer 2009, found that 85% of Twitter users posted less than once a day; that 21% had never posted, that 94% had fewer than 100 followers, and -- perhaps most telling -- 5% of users generate 75% of the tweets (Ashton Kutcher and comScore Executive Chairman Gian Fulgoni, I'm looking at you...) Of course, a persuasive argument may be made that following is as important to Twitter as tweeting is, and in that context we should be careful not to evaluate Twitter traction merely by the creation of content, but also by its consumption.
Professional outlooks toward Twitter may be distinctly binary. On one hand, the more elder hand, they just do not get the point; the other, more younger professionals are entirely energized by this new, cutting-edge technique for engaging into the real-time zeitgeist of human consciousness a la the Matrix. No one seems to be neutral about Twitter, and that in itself is interesting.
ComScore's U.S. Media Metrix shows that in December 2008, only 1% of U.S. Internet users visited twitter.com; by June 2009 that penetration had ballooned to 10.4% -- but, at least with respect to Web site reach, the data show that Twitter penetration has slowed. In July, reach was up a comparatively modest half a point, to 10.9%; and in August, it dipped slightly to 10.6%.
However, Sysomos reported that half of Twitter activity originates offsite through applications such as Tweetdeck -- the reach figures quoted are the share of the online population who hit the site at least once from a computer in a month. Even the most avid Tweetdeck users are likely to make at least one visit to the site in a month. (For comparison, Facebook had a reach in Media Metrix of 46.7% of U.S. Internet users in August.) Facebook also shows 22 monthly visits per visitor, and Twitter with 5. Again, that frequency will understate the true Twitter activity because of posting from off site.
A noteworthy report is time spent. In August, twitter.com accrued 533 million total minutes of usage; web users spend twenty-four times as much time with MySpace, and thirty-two times as much time with Facebook. Twitter is probably more like Google than like Facebook with respect to engagement, lending itself to very short interactions as opposed to deeper dives. Most of the avid tweeters do much of their tweeting from their phone, and mobile traffic is thus far excluded from Media Metrix. It will be interesting to see what the impact is on Twitter usage (and indeed, on Facebook and MySpace, both with aps on my iPhone) when we can look at the total Twitter universe, including mobile access, via Media Metrix 360. Thus far, at least in the U.S., incremental traffic accruing from mobile devices remains quite small for many publishers. Twitter may well be the first significant exception to that rule.

Clearly, Twitter has become indispensable for its avid users. It will be interesting to see how the same avid users tweet in the years to come.