Multiple Communities on one domain!

Okay so I want to create a website that has multiple different communities within 1 domain.

I want to make it so that once they register for the MAIN community that they then have access to all the keyword specific communities.

Like if I had a community about Colors. When you go to the main domain colors.com it would be a community about ALL colors, but then if you wanted to just talk about the color blue you could go to that specific community and everything in their is about blue. but it only requires one registration to get access to all of these communities.


Does anyone have solutions to this? and what would be the best way to go about this. Wordpress? Joomla?

I want each community to have a blog, and forum.

You create one forum and you create subforum like here on BHW you have Blackhat Seo,Blackhat Seo Tools,Making Money(in making money you have adsense,affiliate,emails,within those you have even more).That is the way I would do it.

Is there's anyone else who is interested in this? We've been toying with the idea here at Baybo. It seems like a lot of people desire communities. If you're interested in us building something like this for you, tell us. We'd be happy to make it but we're not sure if it's something enough people want.

I'd also love to hear more about the idea in general. My understanding is you're looking for service which will let you manage a community, as well as sub-communities. Would these communities be focused on premium content (like an amazon marketplace) or on information, like forums and blogs?