Nature Publishing Group has launched a free social bookmarking tool called Connotea. (read more about Connotea)
For those unfamiliar with social bookmarking tools: these are Web-based services that allow you to create an account, then store favorite websites, aka bookmarks, in that account, which is accessible to you from any computer on the Internet. Two of the more famous social bookmarking services are Del.icio.us and Furl. In effect, you're putting your Favorites online, rather than keeping them tied to one workstation.
The "social" part of social bookmarking refers to the fact that you can (but don't have to) make your collection of links public--that is, other users can see what you've chosen to store. An extra-added feature is that you can assign keywords, or tags, to the sites that you store. You choose the tags yourself, and you can assign more than one tag to any given website. Tagging is a more dynamic and flexible form of information categorization than, say, folders.
How is Connotea different from sites like del.icio.us? Since it is targeted at a scholarly community, there is support built in for various tools (such as OpenURL standards, DOIs, and standard reference formats) associated with online journal literature. (See the FAQ for more details.) This makes it possible to bookmark scholarly journal articles from a variety of sources in addition to plain old websites.
The social aspects of Connotea could make for an interesting new form of scientific communication. (What articles and websites are other people in your research group bookmarking? What about colleagues at other institutions?)
The UMass Libraries offer a similar service for managing and storing citations (as well as websites, if you wish) called RefWorks. RefWorks is an even more powerful tool that is an online equivalent to tools like EndNote or ProCite. In addition to storing and organizing citations (and it is possible to export citations from many library databases *directly* into RefWorks), you can automatically format references in any one of dozens of bibliographic or journal citation styles. Unlike EndNote, RefWorks is Web-based, so--like Connotea or del.icio.us--you can access it from any computer on the Internet.
I think of Connotea as combining the scholarly focus of RefWorks with the social capabilities of del.icio.us and Furl. Each service has different strengths, and it's up to each researcher to decide which, if any, is the most suitable.