Dan Counsell:

An app’s name, and the keywords it uses are some of the biggest influencers in search results; all the research I’ve done suggests that the download volume acts as a multiplier on the name and keyword match. For example, If two apps have the same keyword (and rating), the app with the most downloads will come out on top — I’ve experienced this first hand with Clear for iPhone & Clear+ for iOS.

These are some good tips by Dan for third-party developers. I think the bigger theme is that the App Store is now so large, apps have to be treated like websites for a search engine with optimization tricks. This also explains why so many developers run regular promotions or agree to “free app of the week” initiatives (either official or not) – download numbers matter for long-term survival.