Facebook, the second largest social network in the US behind MySpace, added a blogging feature today. They're calling the feature "My Notes", and allowing users to upload images. More importantly, you can syndicate one external blog by entering the URL - however, you can't edit those posts on Facebook once they've been imported. I tested this out and there seems to be no Technorati-style verification to make sure you own the blog - there is, however, a tick box that asks whether you have the right to reproduce the content. The posts are formatted fairly well, although some of the image alignment is lost - if you've got a Feedburner feed, it also imports the FeedFlare units.
The posting form is incredibly simple - offering a title, body, photo upload option and the ability to preview your note. Posts can be tagged and commented on, and blogs can also be set to private. What's more, tagging your notes/posts with a user's name will automatically send the post to that user. Another neat feature: you can post from your cellphone by sending notes to [email protected] - this is the same system that's used for uploading photos. I tried pasting various things into the notes, and it seems that while some html is allowed, Flash and javascript aren't.
See also: Facebook Developers Launches and Facebook's Credit Cards
Facebook Notes
Mashable imported into Facebook Notes