(Search Pad is) a new feature we’re testing on Yahoo! Search that helps you keep track of websites and take notes whenever you do research online. It intelligently understands when you’re in research mode and, if you choose, collects information about the sites you visit. You can create research documents with saved websites, edit and reorder your personal notes, and share them with friends. No more handwritten scrawls, Post-Its or scattered documents. And you can access them from wherever you are.
Yahoo Search Pad is currently only in testing and is not visible to all users. Mean while you can get some information on the project from Yahoo blog.