Android Central: How to hide your Wifi from Google's location database.
I've edited the original post, because I thought I'd saved it as a draft, to be edited later; I've been using the "Add-It" app for Firefox, and I'm not entirely happy with the way posts turn out. Usually, it just gives me a link to the article, but sometimes I get the full article. This was the first time it included a photograph! Anyway, click on through. And don't feed the trolls.
Here's a link to the Official Google Blog's description: Don't you just love the way this is phrased as "Greater choice" for unsuspecting folks who have no idea Googlemobiles might be out there snooping in them?