Hey Gonzo
Well, I have always likened anime/toon content on sites to the comic section in the newspaper. People read the paper for news, sports or whatever, but most take the time to check out the comics cause it's fun.
So adding a "toon" section on any type of site will add to it's value, as well as give your members even more fresh content, which as we know helps retention a great deal.
As for intergrating into a site, I would suggest if possible to get toons or comic's that work well with the site theme, such as bondage, gay, straight, gothic, etc. There are toons for almost all the niches
Then see how well the section does for you, and add as interest grows. Anime and Hentai goes very well with Asian and bondage sites, humorous toons do well on most any type site. Recurring comics are another great way to keep members interest, like any comic book they look forward to the next "edition", so adding a weekly or monthly series is a great incentive for them to hang around. You can find comic series that match most niches as well. And of course you can always commission an exclusive series to match your niche.
h34r: