Aggregation - the only way we can survive information overload from the diverse range of sites and services we flit between:
FriendFeed: keep up-to-date on the blogs, bookmarks, tweets, photos, videos and music that your contacts are sharing.
coComment: keep track of all the comments and discussions you are participating in or observing across the web.
SecondBrain: a content manager that helps you collect, organize, search and share content from multiple online services in a single library.
And the winner is:
A tie between FriendFeed (best interface - less is more) and coComment (best functionality).