Maybe this is a good niche for Yahoo to fit into since they can't really compete with Google or even Bing on search anymore. Yahoo has launched a pair of apps to search for other apps. Yahoo App Search on the PC works on the, uh, PC. Yahoo AppSpot is a mobile search for apps on iOS devices and on Android. What's interesting about this approach is that it's a real search engine whereas the app stores are mostly all about sales ranking. The popular apps stay popular because no one sees anything else and the whole charm of 400,000 apps or whatever is kind of lost when all you see is the top ten.