Should You Build Your Own Social Network?

I’ve been seeing a lot of discussion lately on the concept of custom-created social networks. The idea is that rather than make someone else’s network, say Facebook or LinkedIn, work for you, go ahead and create your own. Hmmm.

A well cited example is Starbucks’ mystarbucksidea.com. While I have been pondering this idea, I was even invited to join one of these custom-created networks at http://gooddogz.ning.com/

I’ve seen data that suggests that leveraging existing social networks can help attract viewers/subscribers to your corner of the space. I have also seen anecdotes about custom networks that quickly attract more members than similar efforts on MySpace and other sites.

The tools to build your own social net are already out there. The platform provided by Ning, a company that promises anyone can build their own social network for anything, seems to be commonly used.

What do you think – is there more power in joining the established social networks or in building your own space that specifically targets the interests and needs of the folks you want to include? Do you have a success story to share about either approach?