Microsoft Live Labs has a new "technology preview" for you to play with. It's called Listas and it's basically a social bookmarking service for keeping track of content you come across while browsing the Web, and sharing it with others. Users can make their own containers full of all sorts of links, and supplement it with text, images, and RSS feeds using a WYSIWYG editor or by just pasting in entire Web pages from their text clipboard. The service is being billed as a way to make lists, but I think its core appeal will ultimately end up as a Web clippings service.
Oddly enough, Microsoft has had their TagSpaces service kicking around since April. TagSpaces gives users a bookmarklet to tag any item they've come across while browsing, and drops it into a giant pool of tags for everyone. Listas is clearly a more advanced effort, and one designed to handle media and collaboration a little better.