A number of app search engines have arisen to confront the so-called “app discovery problem.” Among them are Quixey, Chomp (recently acquired by Apple), Appsfire, Appolicious and Xyologic. Yahoo has built an app search engine; and one can also search Google Play for apps of course. Bing also dabbled in app search for a time.

The central difference between most of these sites and Quixey is that the latter is not simply indexing and searching mobile apps. Quixey characterizes what it does as “functional search” rather than app search. It’s indexing available apps across platforms (including the PC), as well as web content pertaining to those apps.

The idea is that users will enter queries that describe tasks or goals to accomplish rather than specific apps or even app categories. For example, in response to the query “learn french,” the search engine produces a range of results that show mobile apps but also “apps” for Firefox, Facebook, Mac and Windows (both paid and free).