I recently launched a Ning site for the Oakland Museum of California:
It is a community for celebrating Dias de los muertos (Day of the Dead).
Overall it was a good experience for a project with a tiny budget and very fast schedule. There are lots of features on Ning but very limited ways to implement them. It’s very hard to make a Ning site not look like a Ning site so it’s best not to have that expectation.
There are a number of alternatives:
Flux, like Ning, (and more recently KickApps ), it’s a place for sites to easily create a new social network, or bolt a social network onto an existing site, and add users from other platform social networks with a single click.