For the entire history of Bomis from day one until the current day, the percentage of revenue that comes from adult businesses has been under 10%. The bulk of the revenue of Bomis today comes from advertising syndicated from Google; in the past it was at various times Overture and NBCi which provided the bulk of the revenue.
Far from being a "secret", Bomis is a public website that anyone can look at anytime they like. If Bomis is pornography so is much of what happens in R rated movies.
Bomis _is_ a brand which is very different from the Wikipedia brand, which is why I have always insisted on keeping the two very separate.
--Jimbo