Google is testing advertisements on some of its local maps, writes David Galbraith in his blog.
For example, a search for New York hotels shows red balloons for organic results and smaller, blue balloons for so-called "sponsored links."
Galbraith points out that while this may be an obvious move on Google's part, it is still big news because:
"1. The Yellow Pages advertising market is bigger than the entire existing online search advertising market.
"2. Offline Yellow Pages directories will clearly be replaced, over time, by online products, and it looks like maps are how this plays out.
"3. Ad products are where Google makes the money that justifies its gargantuan Market Cap. So a new ad product is a big deal. Now, alongside Adwords and Adsense it has a third revenue source that is in a bigger marketplace."