Thanks for the comment.

If you have actual traffic stats I'd love to see them. ;)

Also, the estimate isn't for "a couple months", but for the past 12 months, and the trend points in one direction. Even less reliable but even more "damning" is Google Trends: http://google.com/trends?q=tumblr,+posterous&ctab=0&...

That being said, your general point is right: nothing is preordained, and the trends could switch around tomorrow, and the picture look much different a while from now. But that's why I have a blog: this is the situation as I see it today. Maybe six months from now I'll eat my words, who knows?