Twitter has changed its HTML title tags on user profile pages to make the site more search engine friendly. Instead of displaying its previous title of Twitter/"username," the site's new title displays the person's name, followed by his or her Twitter user name in parentheses and "on Twitter" after that.
The decision to change title tags is already working out to Twitter's advantage. I performed a vanity search on Google to see where my Twitter profile ranked in results for "Don Reisinger." For the first time, it was on the first results page. CNET News and Webware editor Rafe Needleman's Twitter profile is also displayed in the first Google results page when you search for his name.
I tested the new pages with random followers on Twitter to see if their profiles were on the first page of Google results. They were. In fact, I couldn't find one Twitter user who didn't have his or her profile in the first page of Google results. Even Britney Spears' and Barack Obama's profiles were displayed on the first page of their results.
Twitter hasn't commented on the new title tags, nor has it released any traffic data showing the impact of having Twitter profiles in the first page of Google results, but search pages are coveted territory, especially on celebrity queries. They can drive heavy traffic into a site. It wouldn't surprise me if Twitter is witnessing a spike in traffic because of this.
On a side note: Facebook, MySpace, and Friendfeed profiles were rarely displayed in the first pages of search results.