Being a fan of web sites with a physical location I've felt the need for something that would tell you what sites relate to your local area. Groups Near You does this fairly well. You can add sites and match them up to an area on a Google map. There's no log-in, but it uses your email address to confirm changes and then that site is restricted to that email account. Some real potential if people add enough sites. I did a couple. It's a shame they don't make use of GeoURL to pick up the location of a site and then publish that data on their pages. Maybe I should mail them.
My other toy of the last few days was MyBlogLog. It's a Yahoo service that gives you some nice visitor tracking features for your site and lets you build a 'community' around it. The stats are nice, but I'm not totally convinced yet. I mainly joined in order to check out how their FOAF data appeared on the FOAFster visualisation tool.
identi.ca has been much improved by allowing you to see all your replies in one place. People had replied to some of my 'dents', but I had missed them. I've picked up a few followers who share my interests. These spontaneous communities are fun.