From Google Base website:
Help the world find your content.
Google Base is a place where you can add all types of information that we'll host and make searchable online.
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.
Read more about Google Base at news.yahoo.com.