Back then, free APIs and mashups based on them were the hot thing. (Free geolocation resolvers, Google hat a free search API, Bing as well, FB had one, too, free weather forecasts APIs, etc., etc.) You couldn't be a trendy start-up without providing one. Things have changed a lot since.

PS: I keep a few selected apps from this era on my phone. Once a year I open them and admire them in their data-less beauty. (Favourite one: Partly Clouded) Let's call it software shinto.