Yeah, I'll definitely be turning on Chat. (Didn't want to overload people...I originally set this site up very very basically about a year and a half ago, and showed it to a couple of list people who found even the limited feature-set overwhelming.
I understand what you mean re: forums. I didn't want to pull away from the list, though, so...eh, not sure.
You can also add apps and widgets all over the place (like the earthquake widget on the home page), a music player, and events log/calendar (different from a Google calendar thing...members can actually set up invites and stuff. hard to explain.) Birthday notifications. RSS feeds (both directions - you can feed too and from this site.) AND you can set up groups with their own forums and such, so we could have a fluourescent group, a micros group, marine fossils group, etc. That's one really strong argument for turning forums on, because I don't think Groups work otherwise.
It's also possible to add totally custom HTML content/tabs/pages. It's a spiffy little platform.
Ah, I really can't take credit - except that I know how to customize text in the interface and stuff like that. I love Ning for social networks - you can actually set up a basic one in about 5 minutes. I have a LOT of featured turned off right now. (e.g. We don't need a forum.)
They make it seriously easy.
When the regular website is finished, I'll customize this a bit to look like the website. (I'm kinda liking these colors, though - the dark makes the mineral pictures look gorgeous.)
My family has a completely private site on Ning...great for keeping in touch.