Microsoft Tagspace

I have tried Tagspace before but never ended up using it. Let's see if I might start using it now. I'm still not convinced though. Here is the RSS feed for the AutoCAD tag.

Tagspace Overview

With today's release, you can now use Tagspace to:

• Tag Practically Anthing on the Web--Apply tags to practically any site on the World Wide Web, excepting those that are known to contain offensive, malicious, and otherwise inappropriate content.
• Browse Member Tags--See what other users have tagged and view their personal tag clouds, by clicking on their display names.
• "Tag Drafting"--Subscribe to the RSS feed for a tag (like tagspace).
• "Member Drafting"--Subscribe to the RSS feed for other members' public tagged items (my Tagspace RSS feed here;-), by clicking on their names and subscribing to the RSS feeds associated with their tagged items lists. 
  • "Tag Drafting" and "Member Drafting" are excellent ways to stay up to date, diminish information overload, and approach what I like to call "domain omniscience", at little expense to yourself.

Via Korby Parnell's blogpost

What bookmarking or tagging system do you use and why is it useful?