This seems to have been Twitter's month. It progressed from being a curiosity adored by a tech-obsessed few to the virtual stomping grounds of major celebrities and news networks. It's grown significantly in this time, thanks in part to folks like Oprah and the anchors of the 24-hour news networks signing up and bringing legions of fans with them.

Unfortunately for those who love the service, Neilsen, which is responsible for many of the ratings studies that show how well media products are doing, has its concerns despite the explosive growth.

It just released some information about Twitter, including the finding that 60% of new Twitter users drop out of the service within a month's time. That's quite a bit higher than the attrition numbers for Facebook or MySpace when they were new services, so it might be a problem once Twitter's growth begins to slow.

Thing is, the study only checked visitors to twitter.com, and many of even the most hardcore Twitter users don't actually visit the site; they use external apps like TweetDeck to manage their tweets. Some new users could just be migrating to those apps instead of leaving the service, so it's difficult to say whether or not the study is accurate.