Reading the S1 that they filed, they (obviously) are trying to offset the debt they have through liquidation of their common stock. I can sum up the report as "we are making lots of money, have fairly significant debt, we need to move our shares now". AFF seems to be profitable and I see no reason why they shouldn't go public. While they are generating pretty impressive revenues they can also function as an umbrella in which adult oriented startups can fold into. Possibly providing further value to their shareholders. This is actually a pretty unique IPO , especially in the web sector.
I also think it will be entertaining to see AdultFriendFinder ring the NYSE bell.
The reason why they shouldn't go public : very bad timing in this volatile economy. I don't know if AFF can be categorized as startup, but startups that do not have enough cash flow (the real cash) for 2 or 3 year of expenses and etc should not go for public unless you want to get burned by short-sellers and opportunist. I work part-time in Japanese startup in my leisure time. We are only 10~ people (not all of us are developer) but already generating $4M of net income last year(not try to brag on it, since I'm sure we're not the best) and by the way we did end-year party last night I am pretty sure it's more than doubled. We choose not to raise fund or sell IPO because we feel steadier without it. Unless you have great growth that can ensure market (remember, todays market is mostly based on fear) or you have great trouble and IPO is the only thing that can save you, don't enter the market :)
I also think it will be entertaining to see AdultFriendFinder ring the NYSE bell.