422% growth in traffic is not 422% growth in registrations. There is a solid core of early adopters, but getting mainstream society to start Twittering -- especially when there are similar services offered by more popular platforms, such as Facebook -- will be a challenge.
But MSM seldom get it right. Remember the LA Times wikitorial? Or Wired's Second Life bureau? When's the last time you listened to a podcast produced by your local newspaper, or used the NYT's Blogrunner service? The media is desperate to "get" the Internet, but many times they simply end up jumping on the latest bandwagon, which fades after a year or two.