Why would Twitter turn down a $500 million buyout offer in this economy? The micro-blogging giant reportedly is working on a whole new model that could revolutionize the way we search -- and do business. Twitter wants to offer users the option to "push" queries to some 6 million members, rather than simply "pulling" in information already published on the Web. "You put a question out to the global mind, and it comes back. ... You get feedback in real time from people, not just documents," says Twitter investor Todd Chaffee.