Apartment Rentals, Traffic -- Merging Other Data Into Google Maps

I've been collecting a variety of ways people have been creatively merging data from various places outside of Google into Google Maps for a round-up article. But Wired's Hey Google, Map This! article out today provides all that and more. So check it out and learn how craiglist apartment rentals or Yahoo's traffic alerts are being placed into Google Maps through grassroots efforts, rather than by Google directly.