In this topic, I will try to share my own experience: why we created an application for the iPhone and how we unwound, whether our expectations were met and the site traffic increased.
Why iOS, but not Android? According to liveinternet statistics, in Russia there are 2 times more iOS-enabled devices that are connected to the Internet (which is very important for us) compared to Android.

The
application itself is a reader of
community posts in a convenient form. Its main feature is the ability to download information in a crowd and view it without connecting to the Internet (to save traffic / money).
')
We tried to make it as simple as possible, just downloading and viewing information, so that there were as many users as possible who understood the application.
To achieve our goal and attract new users, we needed to promote the app in the App Store. That is why it was created. Before investing in promotion, we reported on the program on our website. Our users began to download the program and leave feedback.
Further promotion consisted of posting reviews on Apple product sites. We assumed that the editors of these resources could not post reviews of the whole row, they select information and post what will be interesting to readers. Therefore, before writing to the owners of these resources, we waited for the moment when the application rises to the TOP of its section and receives at least a few positive ratings. On the day of the announcement, the application rose to 15th place in the Entertainment section, after which we began to be interested in advertising. Editors worked quickly and posted reviews the next day. A day later we were on the 1st place in the Top of all free applications. Hang out not long, but in the TOP 25 were 3-4 days exactly.
Result
During the first 10 days it was downloaded about 20 thousand times, this is how the statistics look like:

And here is the statistics download information (calls to XML)

And the most interesting. How site traffic has changed after placement. The type-in ​​traffic increased by 2,000 people per day.
Cost
Application development: 70.000 rubles
Promotion of the application: 2.500 rubles (purchase reviews)
Not the cheapest way to promote, but it has a couple of advantages:
1) long-term audience growth
2) promotion of the resource with the help of content: you are not “pushing” annoying advertising to people, but offering interesting content
Underwater rocks
- The application should work on as early as possible the firmware version. Many complained that the program only works with version older than 4.2.
- Prepare in advance for the load on your server and channel, but do not overdo it. We installed a gigabit unlimited channel, which turned out to be superfluous - the load increased only by 30-40 Mb / s
PS We decided to make an application when we already tried all the other more or less budget ways to attract an audience.
PPS I rewrote the article 2 times, I hope it came out useful :)