You can't put the regular shit for desperate morons on 4chan.
Most chaners are fine with being single. They get their porn for free from torrents and LAN parties, and think that girlfriends that won't sit their watching anime and playing WoW with them instead of going out to a movie and maybe fucking in a park are a waste of time.
I say this from actual conversations I've had with people when I made the dumb mistake of going on a Scientology raid. The REALLY sad thing is that some of the chan girls are fucking hot.
Which leaves us with the question of what would work for channers, but also what would work for the outside world? (seriously, think outside the box with me on this one)
Internally, I'm thinking the best thing to do would just be to have 2 banners towards the top and the left, marketing things that chaners would probably get into.
So video gaming hardware, Japanese crap, maybe some game strategy guides, oh, and better ISP services for getting up to illegal shit.
For marketing to the outside world where people are tight arses? Most people have no fucking clue who Pedobear and Friends are.
A range of vinyl toys or plushies would probably sell quite well, just due to cuteness factor. From their, you go on a massive merch run ala Gloomy or HelloKitty, and from there you can launch the fashion line entirely on your own with the capital, instead of relying on CafePress or Zazzle.
Getting in on the porn angle, they need to get a paid site going, like Suicide Girls, but using hot chan girls as the models. "Support 4chan with your TITS or GTFO"... Chicks could donate self cam sets or some shit, and non channers could pay $10 a month or some shit.
What I find odd here is that 4chaners aren't all that stupid. Yeah, there are a lot, but there are also people like ****** and ****************** on there that do the marketing shtick, and could easily give moot advice on how to start making some money off of it.
Hell, moot himself could just explain the massive costs of keeping it running and ask people to buy stuff through his links by having a page of "Support 4chan: Buy shit here" or something.