For reasons that I can barely grasp, I just spent the last three hours going through the most popular tags on both MyDD and Dailykos. I have compiled the compelte results in a PDF which you can view here, sorted by most popular overall, most popular issues, and most popular people:

MyDD and Dailykos Tag Popularity

It is hardly a complete study, but I just don't have the time to go any further with this today. I did spend a lot of time determining which twenty-five people have been talked about most frequently on MyDD, and I think the rankings are quite fun. For every person, I added together all of the many tags that refer to that person. The number in parenthesis indicates who often a person is talked about in relation to the most talked about person:

1. George Bush (100.0)
2. Joe Lieberman (63.0)
3. Ned Lamont (57.9)
4. Hillary Clinton (35.9)
5. Barack Obama (30.4)
6. John Edwards (26.9)
7. Nancy Peolosi (24.2)
8. John McCain (19.2)
9. Dick Cheney (17.4)
10. Jim Webb (16.7)
11. Howard Dean (16.5)
12. Al Gore (15.2)
13. Russ Feingold (13.9)
14. Rahm Emanuel (12.6)
15. George Allen (12.3)
16. Mark Foley (12.2)
17. Karl Rove (11.9)
18. John Kerry (10.1)
19. William Jefferson (9.9)
20. Eric Massa (9.2)
21. Tom DeLay (8.6)
22. Patrick Murphy (7.7)
23. Jon Tester (7.1)
24. Bill Clinton (6.8)
25. Mark Warner (6.5)

Keep in mind that MyDD only introduced the tagging system thirteen months ago, so these rankings only reflect that time frame. Maybe I will do more of this later on. Anyway, check out the full "study" here.

Update: Some shoddy work on my part. Harry Reid is actually 14th, with 117 stories for 12.7%, and Wesley Clark is actually just ahead of Mark Warner, with 62 stories for 6.7%. So I guess it is a top 27.