Rob Hof of BusinessWeek has the details on Edgeio, the formerly supersecret startup led by Keith Teare and Mike "TechCrunch" Arrington. The startup apparently plans to make the tag "listing" its backbone and RSS a core listing content delivery mechanism for moving into classifieds, which is currently pervaded by the likes of eBay and Craigslist.
The way Edgeio works is that bloggers would post items they want to sell right on their blogs, tagging them with the word "listing" (and eventually other descriptive tags). Then, Edgeio will pluck them as it constantly crawls millions of blogs looking for the "listing" tag and index them on Edgeio.com.
Also, Edgeio sends a trackback to the blog, providing a way for the blogger to go to Edgeio and modify the listing, adding other tags such as "autos" and other data that will further help the listing appeal to potential buyers.
Edgeio will make money on fees for sellers who want better positioning in results, ads and lead generation. Keith is quoted in Rob's post: "EBays and Craigslists become unnecessary and the tolls they charge become unreasonable." This will be fun to watch as it unfolds...