Several days ago Yahoo announced support for something called the common tag. In short, it basically gives developers a way to tag their content in a more unified way.
Vanessa Fox has the most detailed explanation of how this all works. In fact, Yahoo's post on the topic is almost unusable.
So please go skim her article and then come back here and let me know if you plan on giving this common tag a try. Personally, I doubt I will.
Here is the poll:
Forum discussion at Sphinn.