base.google.com

It appears to be ALMOST live now - if I could only log in, all I get after a brief preview session is the Sign in page. (As also noted on Google Blogoscoped).

My prediction is that the Google Base will be a bigger deal than GMail. It's already got the potential to beat out sites like Craig's List as is: when combined with a Google Wallet service, it'll become a marketplace similar to Amazon's Selling at Amazon or even eBay. I can't wait for the API.