A post in the state-o' the blogosphere series that's of particular interest here. Team Technorati take on Tags. As the stats & charts show, there's lots of folks tagging their posts & using the mechanism for all sorts of purposes:

* Growth has been tremendous in the last 6 months: Technorati has tracked over 25 Million tagged posts from January to July of 2005
* About 300,000 posts with tags were tracked each day at the end of July
* About a third of all blog postings use tags or categories
* People are tagging more than blog posts: Popular services include tagging photos and links (social bookmarks)
* About 12,000 unique tags are discovered each day
* Tagging is growing in languages outside of English as well, including high adoption rates in asian languages like Chinese and Japanese