This was pointed out on #london.pm IRC earlier: http://www.aboutus.org/
It's basically a website about websites, running on MediaWiki. It has a bot that crawls the web finding out about various websites and making them skeleton pages which people can then add more details to. It really looks quite nice.
It already has a page for openguides.org: http://www.aboutus.org/OpenGuides.org
but it doesn't understand subdomains so you have to add e.g. london.openguides.org boston.openguides.org manually. I added RGL: http://www.aboutus.org/London.randomness.org.uk
It might be worth all guide admins taking the time to make sure their guide's on there, and adding a couple of nice screenshots. And of course we'll all want to add each other to our "related domains".
(Alternatively, if you decide you hate the whole idea of AboutUs, please ignore the suggestions in this mail and instead treat it as a warning that your domain information may already be on there. Note however that if you use their search box to search for your domain, if it hasn't already got it then it will add it.)
Kake