Cadmus is a real-time service that manages your stream (Twitter, FriendFeed and RSS) by displaying the most relevant content since the last time you checked in. It helps you get caught up on what you have missed. You can access Cadmus simply by signing in using your Twitter account or by using the API that allows you to view your filtered stream anywhere.
Filtering, curation, aggregation and relevance have long been touted as the next important steps for social media. In actual fact we've had curation services in the form of Digg, Reddit, StumbleUpon, Delicious and many more for a long time. However, the questions "How do I find the blog post, tweet, facebook update, photo or check-in that is most relevant to me?" and "How do I know I've not missed a really important piece of news?" are still asked daily. So, there still isn't a definite answer - or a definitive service. Cadmus started off as a "real-time filtering service" for a product called ViewPoint, but has grown into a self-standing application and the Cadmus API can help users and developers answer these questions.