Newsvine is a rather cool new web based news service. It offers a nice, clean interface with newsfeeds from the Associated Press and other sources. What makes Newsvine unique, though, are its community based features. Users can post a comment on any story, and can "seed" Newsvine by posting links (with commentary) to outside news sources. You can also post original news-style content to Newsvine and share it with the community. You can also create a "watchlist" of topics or authors of interest, and a customized page will be created with news on that subject. Everything is RSS enabled as well, making integration with other apps very easy.
Newsvine is in semi-private beta right now. I have a few invites, so if you are interested in trying it out, let me know.