Twitter has become a popular pastime for many who like to update their daily thoughts and activates, as well as for the voyeurs who just enjoy reading the tweets. Last week, the market share of visits to Twitter surpassed Digg for the first time since launch and was ranked #84 (one above Digg at #85) in the Computers and Internet category. A big driver of traffic to Twitter last week was around the US Airways plane crash in to the Hudson River last Thursday, driving many posts and updates about the situation. One photo of the plane taken by Janis Krums, was viewed by many people via Twitter and was subsequently used across a number of traditional media outlets.

One major shift that has occurred is the increased traffic to Twitter from Internet users aged 25-34. During the same time frame last year, 12% of Twitter’s traffic was represented by those aged 25 to 34, which has increased to nearly 45% for the 4 weeks ending Jan 17, 2009.

In comparison, Digg’s share of visitors aged 25 to 34 was 20% during the same time frame.

Also interesting is Twitter’s clickstream, where Digg relies heavily on traffic from Google (38.8% last week) while Twitter receives a higher share of traffic from social networks, which is mostly due to the applications which integrate the services. For example on Facebook, the Twitter application has over 104,000 active users where status updates can be linked to Twitter updates.

One caveat is that a significant amount of twitter activity takes place on mobile devices (especially since there are several twitter apps for the iPhone), which is not measured here, so the impact of Twitter is actually higher than solely web visits. Although this only tells part of the story, judging by the amount of tweets about today’s Presidential election, we’ll continue to see Twitter’s traffic increase.

Heather Dougherty

Heather Dougherty is Director, Research at Hitwise. This piece originally appeared on Hitwise's analyst blog here.

Image by –nathan