In July, Dave Naylor spotted a "Twitter loophole" in the bio section of Twitter: Twitter nofollows users' web sites but links in the biography were actually not nofollowed. When Matt Cutts read the post, he notified Twitter's staff about the issue. Consequently, Twitter made some changes to disable the links in the biography, a move that appears to have occurred yesterday.
The move has hardly been received well by the search community. In several blog posts, one by Kevin Gibbons and the other by Rae Hoffman, one wonders why Twitter decided to make this change and they suggest alternatives for how Twitter should best handle it.
The problem isn't necessarily the abuse of the system, which might be something that Twitter thinks can be a problem, but more about the fact that people who use Twitter are the ones propagating that profile and building up their solid account. As such, the mindset is that Twitter should not penalize users who have already established themselves as active community members.
Perhaps, then, Twitter should look for an incentive program for good contributors rather than penalize everyone. Kevin suggests a good compromise:
... in my opinion Twitter could learn a great deal from the way Sphinn and SEOmoz reward the active members in the community. Sphinn nofollow all submission links until they hit the homepage and SEOmoz nofollow profile links until you reach 100+ user points.
At this point, I'm compelled to agree. Nobody loses here. Twitter members who have been active for a certain amount of time or who have established themselves should not be impacted.
Forum discussion continues at Sphinn.