
I have created two social networks of my own at Ning.com. One is centered on my Travelography Travel News podcast (at http://travelnews.ning.com), and the other is on Responsible Travel and Sustainable Tourism (at http://responsibletravel.ning.com).

It was very easy to create these, though doing more customizing will probably take some time. In particular, I would like to add a Google Map mashup, which is found a quite a few of the social networks (such as the Travel Tips one, below). The networks with these maps appear to be from version 1 of Ning.com, and is not a standard tool built into version 2.0. In fact, if anyone has some tips on how to create a map mashup and add it to Ning.com, I would appreciate the help.

For a video introduction and tutorial to Ning.com, go to the Scoble Show blog. Also see Ning reviews on Tech Crunch and GigaOM.
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NEW (7 Sept 07): There are other web services similar to Ning that may meet your needs better. TechCrunch.com reviews nine of them here.