Hot on the heels of Digg's new short URL feature StumbleUpon's founder has announced - albeit somewhat cryptically - that they may be working on their own truncation tool. "su.pr is coming," reads the Twitter update, though the link currently redirects to StumbleUpon.com.
The moves definitely make sense for both sites. With so many Twitter users sharing links via shortened URLs, it presents an excellent opportunity for Digg and StumbleUpon to drive more traffic back to their sites.
It remains to be seen if su.pr will stand out from the pack - there are so many good truncators available already that StumbleUpon will need to offer something unique. Of course, simply adding a button to their wildly popular toolbar is a good place to start.