Our friends at Wowhead hav just announced the launch of a new site feature that should make many players very happy indeed: a collection tracker! You can now use Wowhead to track your characters' possession of pets, mounts, titles, achievements, and recipes. The new feature was green lit thanks to the popularity of their recently-implemented quest-tracking feature, which has been a big hit.
The new collection tracking feature includes options to exclude items that fall into certain categories -- the example used by Wowhead is that of pets only available from WoW's Collector's Editions. In this way you can hide any items you may not be interested in pursuing, either by blanking out entire categories of items (i.e. exclude anything Horde-exclusive), or you can manually select individual items to exclude as well. Hop on over to Wowhead's announcement page to check it out!