I am a long-time mineral collector (since I was 10 years old). Since 2006, I have also been a mineral dealer. At any given time, I have several hundred mineral specimens for sale, in all sizes and price ranges, on my web site - OBG Gems & Minerals.
There is also an active RSS feed on the left side of this page, titled "Mineral Specimens", which is continuously updated as I add new specimens. Just click on the title of the one you are interested in and it will take you directly to that specimen.
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.