With each emerging content type comes the ever-present need to help users find it. While text-based search has continued to evolve, effective tools for rich media are still nascent. For the Web’s hot content-type du jour, podcasting, search tools have only just started to appear, though this search niche is poised to heat up: Forrester Research predicts that 12.3 million U.S. households will listen to podcasts by decade’s end; the Diffusion Group estimates the U.S. podcast audience will be at 56 million by 2010.