Six Apart is releasing a new plugin for Movable Type this morning called Activity Streams that let MT users create a news feed and add it to their blog. Similar to the FriendFeed, which I checked out back in October, MT users can plugin their various affiliations with other social services and present all the information in one place where they are already publishing content--their blog.
MT's creators said the plugin is different from services, such as Plaxo Pulse, because you host it, not a third party company. Hosting it yourself keeps your login information in your hands. MT also added privacy options, similar to Facebook's news feed, letting you hide stories you don't want to share entirely, or on an ad hoc basis.
If you do want to share, the service is designed to work with other MT users contributing to the same blog. It'll break up each action by user, and by each set of actions by day. You can see an example of it in action over on Movable Type's team blog.
Activity Streams works with 75 services now, and MT's creators said they have plans to add more services. MT users need to be running version 4.1, and have the plugin installed. There are already a handful of examples of Activity Streams in action on MT blogs, ranging from an entire page to a blog's sidebar. You can check out the examples here, here, and here.