Congratulations to David Tosh and Ben Werdmuller for the alpha release of their social network/blogging/e-portfolio web application called elgg. Right now, it's invite-only, but it shouldn't be hard to get an invite.
It's working pretty slick -- they've combined some simple ideas to create something powerful. The ability to share and tag files puts it a level above a system like Livejournal, although it has much in common with LJ (like customizable templates, decent profiles and a great permissions system) -- RSS is in there already and FOAF compatibility is on the way. They're even planning to release the code as open source and keep developing new features, which makes the future seem very bright indeed.
The developers are also participating in an e-portfolio discussion this week hosted by Maricopa.