As of tonight, the much-anticipated Google Base is live. Having just landed home from a conference, I haven't had time to try it out, so for now, I'll have to just point you to Danny Sullivan and Gary Price at Search Engine Watch for the details.
Judging from their comments--as well as one from Google's Salar Kamangar, who said in a Wall Street Journal story that "Some people will use it for posting commercial things, but I'm not sure at all that it's going to be a primary usage"--eBay and others may not have much to fear just yet. That seems to indicate that executives at eBay, which had seemed to be one prime target in the crosshairs of Google Base, may have been right when they appeared to be unworried about Google Base's threat. Or maybe Google's just being cagey.
More to come when I have a chance to check it out.
UPDATE: Still no time to try it out, but the reviews keep coming in. Mike Arrington at TechCrunch says "yuck," but Dave Winer, as well as Brian Benzinger at Solution Watch, seem more optimistic. OK, my turn to try it out, more later....