I have an iOS application - an alarm clock. I released it a little over a month ago. Initially it was paid, but when I saw there were virtually no purchases (from 0 to 4 a day), I changed it to be free for a period of time. When it become free, in less than 10 days it has been downloaded more than 30,000 times, and more importantly (I think) it moved much higher in the search results when the user searches "alarm" - it reached 20th place in the results. During that time I also received very good reviews in the AppStore. But today I changed it back to paid, and now when I search "alarm" my app is shown at the bottom of the 4TH PAGE. Given that one page contains 120 apps, this is very bad for me and I don't understand why this happened. Can anyone tell me how does AppStore ranks search results and is there a way to move my app higher in the rankings, please? :) Huge thanks!
I'd venture to guess and say that the App Store ranking algorithm is a company secret, much like Google's web search rankings. It seems to me that the radical changes in placement you are witnessing are as much the fickleness of App Store customers as anything else.
Correlation isn't causation by any means, but it seems fairly clear by your description of the events that if you want a lot of downloads you will either have to make it free (and perhaps ad-supported?), or your alarm clock app needs to do something so unique amongst the plethora of alarm clock apps that customers will feel compelled to pay for it.
The rankings are complicated and take many things into account. It's not publicly disclosed and the rankings are being tweaked over time as Apple learns what customers want (filtering shill reviews from demo codes, weighting reviewers and stars, aging older data out faster, recent sales data seems to be very important.) Also, there has been a see saw of whether a recently updated app, an app with an alternate availability date and the original date of release is sorted to the top. I would expect that to settle down to a mix of all three for a blended ranking.
In a nutshell - focus on making your app the best it can be - rest assured Apple will want to promote heavily the apps that make the most people happy. Don't try to SEO the store but instead make a small core audience very happy and expand from there. Make them so happy they legitimately want to leave stars and reviews. Initially apps got a bump asking for reviews and stars, but it seems lateely to have a negative back lash effect. How do you feel when you are interrupted at exactly the moment you chose to use an app and it hits you with an ask for promotion. Many reviews now express that rather than what is good about the app.
You will hopefully get your moment in the sun and then it will pass. Only the hard work of long term word of mouth will help make an app a long term success.
Do ask for user feedback in the info or settings menu or in an opt-in mailing list from time to time - somewhere your die hard curious users will find and way out of the way of the normal function of your app.
I would follow the blogs of some of the best developers and they write often about when they notice changes and trends in the rankings. There have been purges of junk apps, purges of ones that obviously game the keywords, ones that had shill reviews (nonsense 5 stars for obviously crappy apps).
Here are several blogs worth watching for words of wisdom and astute app store policy commentary: