To find out, go to your user profile, and hit (near the bottom) "Show general statistics for this member." Then go to the bottom, and it's the same graph as this topic title. And post your top 10 boards, in order, descending.
Mine:
1. Everything Else
2. TV, Movies, & Music
3. Nickelodeon
4. Bikini Bottom
5. Computers and Video Games
6. The Pineapple
7. Games
8. Easter Island Head
9. The Waste Land
10. Site News