Examples of items you can find in Google Base:
You can describe any item you post with attributes, which will help people find it when they search Google Base. In fact, based on the relevance of your items, they may also be included in the main Google search index and other Google products like Froogle and Google Local.
Just what does Google have in mind? The last sentence there really speaks to what they're after: eBay, Craigslist, and classified ads. Users will be able upload all kinds of items for sale, and you'll be able to geo-locate them, compare them, and search them via Google. Think about it. When using eBay or Craigslist, how often do you think "I wish I could search this with Google"? Recall, too, that Google has a payments service in the works.More details over at Ars Technica.
Over at Google Blog the company's product marketing manager Tom Oliveri posted a reply to this rumor:
You may have seen stories today reporting on a new product that we're testing, and speculating about our plans. Here's what's really going on. We are testing a new way for content owners to submit their content to Google, which we hope will complement existing methods such as our web crawl and Google Sitemaps. We think it's an exciting product, and we'll let you know when there's more news.