App Ratings and Reviews

My experience is that about 1 in 250 people who buy an app rate it and about half of those write a review. This is a very rough estimate based on a small sampling of 4 apps.

iAd

Starting research:

http://www.vellios.com/2010/09/23/supplement-iad-with-admob/

http://www.vellios.com/2010/08/19/iad-profit-the-truth/

http://shopsavvy.mobi/2011/05/12/my-300-app-experiment-9-months-later/

In App Purchases

Less than six months of experience/data, but I'm finding in app purchases .99¢ to account for 10 to 15 percent of revenue on $1.99 app. Users appear to appreciate the option to buy content specific to subject matter they're interested in.

I've noticed more and more free apps with in app purchases in the top grossing lists and this article substantiates the trend.

Facebook iOS SDK

In the end, every app developer is faced with the question 'How do I get people to see my app(s)?'. One step towards this was adding a button that made it easy for the user at the end of the game to share a quote on Facebook. The idea of putting our logo and link next to the quote on our user's news stream seemed like an ideal way to increase visibility.

Wrong. Facebook documentation is fragmented across many versions of the SDK. The latest version at GitHub is by far the best, it's clear and I found no memory issues with Instruments BUT Facebook's backend frequently stops working. I've released two products that worked when released and then at some point stopped working, then started working, then stopped… And the real shocker is how few times this option gets used: User's push the "Share on Facebook"  button only 1/3 of 1% of games played.

If I knew then what I know now, I would have never included Facebook support, but now I'm stuck with it. It's a huge time sink and source of frustration - user's send emails like "it worked yesterday and now it doesn't".

Article on Facebook APIs

App Submission

Based on 15 submissions, apps have taken from 5 to 8 days to be accepted or rejected. I've had an app accepted on a Saturday, and heard of other developers being accepted on Sunday. Apps usually show up in iTunes within 2 hours of receiving the "Your app status is Ready for Sale" email. Once an app is accepted you cannot change it's keywords or categories (e.g. Games/Puzzle). Apple's approval process for my last Cryptogram update only tested "In App Purchase" and "Game Center" - no other functionality was even looked at.

Usage tracking

Tracking how your users use an app can be enlightening. For example, I was surprised that people look at the About screen about as much as Help - and that few people do either, about 1 in 7.

I've been experimenting with Google's AppEngine to store anonymous information like page views, clicks, and scores. It turns out to be cumbersome to export data with AppEngine and with over a million score records I've exceeded the free quota. I'm now looking into using Google Analytics iOS SDK. It's very easy to integrate into an app and provides lots of reporting functionality.