In the age of mashups, APIs are the lifeblood of developers looking to impact users' lives with visualizations and recommendations based on open-access to data. Want to find a nearby restaurant with a high rating that serves vegetarian cuisine? There's a service out there can provide that information, most likely relying on various providers like Yelp for business information and Google Maps to show how close it is to you.

But are some APIs naturally more useful than others? As a public-facing service itself, Google Maps is an invaluable provider of location-based information with such offerings as directions, local businesses and street-level views. But as an API providing machine-readable data to other services, how does it stack up to others online?

After perusing the APIs listed on Programmable Web, I uncovered the undeniable popularity of Google Maps as an API, perhaps a result of our need for location-based data in all parts of technological lives. In the visualization shown above, each red 'planet' represents a member of the popular Google API family. As evidenced in the program, Google Maps by far takes the lead as most popular API, with about two thousand mashups relying on its service; Google Search, the second runner-up, has only 125 mashups.