I've found ning sites particularly useful for creating ad hoc social networks with a specific audience, content or goal. Wikis are better for collaboratively creating content, but lack the social elements of a ning. You can set customised profile questions on a ning that help your members learn useful and relevant information about each others, without all the extra personal detail they'd get on a site like Facebook.
The problem I've found is that they lack lightweight tools for notifying members of new content or activity - the RSS feeds supplied are very useful if your audience already knows how RSS works, but otherwise you have to send 'broadcast' messages to members. Done well it could be a useful digest of news, but it feels a little spammy. cheers, Mia -------------------------------------------- http://openobjects.blogspot.com
