Hey, Barclay, thanks for joining in. Well, if you read the help, you'll see that you can upgrade to a paid version where you can run your own ads. So, it's a great way to build a community, see how it works out, and then switch to a paid model if you think it's worth it.
I'm still trying to figure out exactly what I want to do with Ning, but I really like the concept. The easy management is definitely a plus. I'm still new to this social networking thing, but it does look promising.
I'm not a big user of this type of social networks, but I've already found some good uses for Ning: a free forum, such as this one, and a private community site for my friends.