Benjamin and Joost-Wim, two interns here at Tam Tam, have been working at a very cool solution in MOSS 2007. Their goal was to create a knowledge management solution in MOSS 2007. Of course there are some tools out there that support rating and tagging and cloud tags in SharePoint. This solution however offers a rich user experience of those mechanisms, personalized (this is very cool) and full integration with SharePoint search and Ontolica search!
I've put some screen shots below, but I'm sure the movie they created tells the whole story in 2 minutes.
Tagging, and personalized rating integrated in SharePoint list, sort the lists by rating
Add new or existing tags.
Rate the items, both personalized and global
Integrated in search
Or just watch the video here