Google Base basics
Google Base takes a completely different take on this. Users set their own taxonomy of attributes and categories. As more users add content to Google Base, the overall number of attributes users select for any one keyword or product increases as well. All Google Base needs to do then is apply a bell curve to measure the most popular attributes or categories selected for said keyword search term and tada! you have a universal attribute structure which constantly adjusts and improves based on what the community of users generate. At first this process is a complete mess, and is hugely open to abuse by spammers, since the 'folksonomy' doesn't have sufficient number of attributes inputted (hence my search result for 'recipes' turning up jobs and job type as attributes below - this is already gone btw replaced by the more appropriate cuisine and ingredients). But as 1 million listings turns into 100 million (so long as its not all spam) the system essentially improves itself, and the most popular attributes become the most appropriate for display to buyers. Google rids itself of the work required to select attributes product by product since the user community does the work for them... Go spam go!
Update: Here's a story about the lagging Froogle. Just in case you didn't believe me ;)