As a student work, I would say this one can count. Tweetcatcha [parsons.edu] visualizes the tweets resulting from the latest news articles that appeared during the last 24 hours on the New York Times website. It
uses the NYTimes Timeswire API and Twitter to discover the tweets according to the titles and URLs of recent news articles. Searching through Twitter for valid URLs was made much easier by using BackTweets, a service of BackType.
All the tweets are arranged around a set of 24 rings, one for each hour in the day. The location of a tweet is based on the time difference from the article posting to the time the tweet was created. If a tweet was posted less than an hour after the article, then it would be very close to the inner most ring, and vice versa.
Be patient, as the viz application seemingly takes a long time to load. More detailed infos at the authors' blog post.