A post on a BoardTracker forum pointed to the use of tags on Slashdot. In addition, the post highlighted the use of tags on BoardTracker's own forums. Sounds like there will be more tag based features to come:
Tagging is very popular these days, particularly among bloggers, and of course BoardTracker has brought tagging to forum threads too as you can see in the 'topic tags' above. For an example of these tags displayed on boardtracker have a look here..
We are rolling out several new tag related features for boards soon also.. watch this space!