Google continues to amaze me with their rapid fire implementation of new (and free) web services. Just when I start to believe they're going the Yahoo route with a new product that cannot readily generate advertising revenue as it's sole source of income, Google shows another innovation in advertising.

This time it's advertising on Google Maps (via Digg). Having store names visible on the buildings in Google Maps is remarkable because of the addition of satellite photos to Google Maps and the widespread interest in Google Earth.

The do-it-yourself approach is cute too. I've seen this around airports before, but this Google product makes makes this much more interesting.

Every time this kind of news comes out, it seems clear that Google has really not strayed from their core business -- advertising.