Today, Yahoo! launched My Web, your personal search engine. Among its features is the ability to save URLs to folders for later reference. These folders can optionally be made public, enabling them to be shared with the rest of the world.
We've also exposed this public data through a couple of webservice functions. listFolders lets you get the public folders associated with a Yahoo! ID, and listUrls lets you retreive the URLs from any of those folders. There's a lot of potential in these functions, and we're looking forward to seeing some applications using them.
For more on My Web, be sure to check out the Yahoo! Search Blog.