Getting a handle on the kind of people that attend Anime Detour and make up its dynamic is a little tough. As far as I know, nobody has done a survey of the membership to figure out what attracts people to the convention*, much less what the main interests of those people are, but I think we can make some educated guesses based on what's popular at Detour.
Gamers are perhaps the most obvious group, and also one that presents some problems for the convention. Detour caters to console gamers and rhythm gamers (people who play DDR, Pump, and now various Wii games) as well as some RPG and CCG gamers. Jeff has also run some Go panels which have been well received. The thing about gamers is that while we want to use Detour as a tool for building community in anime fandom, console gamers unfortunately tend to hang out in the game room a lot and not mix with other folks. This is part of the reason Detour has never had LAN gaming despite offers by various people to set up and run a LAN gaming room; things get funky enough in the console gaming room as it is, and besides we've never really had the excess space to devote to another gaming venue.
Cosplayers are another major group, and I include here "casual" cosplayers who attend to show off their costumes in the hall and don't enter the formal cosplay competition. There's some overlap between cosplayers and the costumers who populate the Convergence and Marscon masquerades. Workshop panels that discuss techniques of costuming and the greasy organizational stuff behind the cosplay have been consistently popular.
Artists. People who draw fanart or original sketches or make plushies and stuff. We never had enough room for all these people in Artists' Alley while we were in the Thunderbird, and it'll be interesting to see how much more space they get at the Crowne Plaza, to say nothing of whatever hotel Detour winds up at in 2010. This is one of the subcultures in anime fandom that I see as truly unique and in need of encouragement, and I hope it gets more room to show its stuff in the coming years.
After this point, though, titrating out discrete subcultures within anime fandom is a tricky business. Fanfic is popular, and we've done panels on making the transition from fanfic writer to professional author. People also come to anime conventions to get a look at anime they haven't seen before, and both the video rooms and AMV exhibitions/contests speak to this. Voice actors and actresses are a big draw, since a lot of fans like to hear what they have to say about the series they're working on, the state of the industry, etc. Plus, by and large, we've been lucky and most of our guests are really cool people who enjoy engaging with the membership.
We also get a large number of people who come to the convention mainly to hang out with their friends. They might be into anime or manga, but they aren't fanatic about it; they don't have a favorite series per se and probably couldn't tell you the difference between yaoi and yuri. They're at Detour for the party, and to the extent they behave themselves and don't shit up the premises we're okay with that - their money is just as good as anyone else's, after all, and if there's really nothing at Detour to hold their interest, eventually they'll lose interest (despite their friends) and stop coming. It's not like we have free beer for them, after all.
Oh yeah. We also get those people who really don't have a whole lot of interest in anime, manga, cosplay or any of that nonsense, they just come to work at the convention because they like to work on conventions. These are not to be confused with people who *do* like anime and manga but just don't have time to indulge themselves in fannish pursuits at the convention because they're working 12-20 hours a day while the convention is running. Anyway, I'm still not sure what draws these people to Detour (actually, some of them are anime moms who show up as chaperones and work a volunteers/staff to avoid terminal boredom), but we're damn glad to have them.
*I expect to have time on my hands again next year, so I might as well do this.
This is mainly based on what I saw and heard in six-plus years of working on staff, and as always, I'm grateful for input from others.