[Writing in Orange] is a group weblog that seeks to develop a network of bloggers and other writers in Orange County, California. Twice a month, we seek to create community by posting a topic to which all bloggers can respond. Among our goals is to bring more Orange County journal keepers and other writers into the blogging community with these exercises. We also post a calendar of events with activities of special interest to writers and bloggers.
[LA Blogs] does even more for Los Angeles. It serves as a nexus for all Los Angeles area bloggers and as a general calendar of events for the greater metropolitan area (including Ventura, Orange, Riverside, and San Bernardino Counties). Writing in Orange, I should add, is not a secession movement or an expression of dissatisfaction with Jonah's fine work: we seek to focus and develop new bloggers in our narrower region within the Los Angeles blogging community.
Added 17th April '04:
[London Bloggers] based around a map of the London Underground transport system.
[UK Blog map] database-driven by postcode (zipcode) with interactive data-sensitive mapping.