BetaNews reports on Yahoo! opening up their own Maps API to developers. However, it isn't the same as Google's system, as reported a day ago here.

Yahoo! is using XML, with all the gory details on it's developer pages. The practical upshot of all this map goodness is that web developers will have real choices when it comes to building better content (store locators are popular, but there are many value-added services possible with these tools). Whereas Google uses JavaScript, Yahoo! uses XML and geoRSS (an extension of RSS 2.0).

On the business side is how each search company is paying for all this "free" goodness. Yahoo! makes a developer link to their site (and register first). Ads are pulled in direct from Yahoo! in this manner. Google, on the other hand, has merely hinted at the prospect of future ads... We shall see.