Regarding the Twitter vs. Blogger thing from earlier in the week, I took another stab at the faulty Twitter data. Using some educated guesses and fitting some curves, I'm 80-90% sure that this is what the Twitter message growth looks like:
These graphs cover the following time periods: 8/23/1999 - 3/7/2002 for Blogger and 3/21/2006 - 5/7/2007 for Twitter. It's important to note that the Twitter trend is not comprised of actual data points but is rather a best-guess line, an estimate based on the data. Take it as fact at your own risk. (More specifically, I'm more sure of the general shape of the curve than with the steepness. My gut tells me that the curve is probably a little flatter than depicted rather than steeper.)
That said, most of what I wrote in the original post still holds, as do the comments in subsequent thread. Twitter did not grow as fast as the faulty data indicated, but it did get to ~6,000,000 messages in about half the time of Blogger. Here are the reasons I offered for the difference in growth:
1. Twitter is easier to use than Blogger was and had a lower barrier to entry.
2. Twitter has more ways to update (web, phone, IM, Twitterific) than did Blogger.
3. Blogger's growth was limited by a lack of funding.
4. Twitter had a larger pool of potential users to draw on.
5. Twitter has a built-in social aspect that Blogger did not.
And commenters in the thread noted that:
6. Twitter's 140-character limit encourages more messages.
7. More people are using Twitter for conversations than was the case with Blogger.
What's interesting is that these seeming advantages (in terms of message growth potential) for Twitter didn't result in higher message growth than Blogger over the first 9-10 months. But then the social and network effects (#5 and #7 above) kicked in and Twitter took off.