"As discussed in the comments, Nielsen is only able to measure return visits to Twitter.com: how many people set up a desktop application like TweetDeck (TweetD

"As discussed in the comments, Nielsen is only able to measure return visits to Twitter.com: how many people set up a desktop application like TweetDeck (TweetDeck reviews) and continue to Tweet, but never return to Twitter.com? " on the other hand, having to set up additional software just to make one's twitter stream sensical, is a large barrier to entry. i bet more people get turned away than take the next step.