After a lot of rumors Google Base is finally live (in beta of course :-)
I have tried to use it the last month without much luck as it has been down more than up. It seems a lot more stable today even considering the initial onslaught after they announced the service. The idea behind Google Base is simple: write an entry and describe it with the proper attributes. Items in different categories will have different attributes; Job Posts have an employer attribute whereas Recipes have ingredients etc.
I am still playing around with it so I haven't made up my mind. Is it a big categorized community blog, a content editing system, another craigslist, or neither, or a mix of them all?
The engineer in me says it is one big configurable DB, but it will be very interesting to see what people make with it and what they use it for...