AdMob has released Download Tracking for iPhone applications, letting advertisers accurately monitor App Store conversion rates.

Advertisers will know the amount of clicks on an ad that lead to a completed download of the advertised application enabling them to precisely measure their return from advertising on AdMob's network. AdMob claims reach of more than 8.4 million unique iPhones and iPod Touch devices worldwide, as of December 2008.

"AdMob is a leader in monetizing applications and works closely with developers to monetize more than 1,000 iPhone applications," said Nicole Leverich. "By launching the AdMob iPhone Download Exchange we are giving application developers a new way increase the discoverability of their application and drive downloads, which is an essential component of building a thriving iPhone app ecosystem."

Advertisers can use Download Tracking to view and track multiple applications and drill down to look at conversion rates by specific ad and for specific dates.

AdMob's advertisers are already using this new information to write better ads, calculate their return on ad spend, tune their App Info pages, and develop better pricing strategies.

"One of the biggest challenges for iPhone developers is increasing consumer awareness and driving downloads of their applications," Ms. Leverich said. "AdMob's new iPhone Download Exchange addresses this big challenge by enabling iPhone app developers in our network to use a portion of their ad inventory to promote their application and drive downloads in a new way."

A limited group of iPhone applications began testing AdMob's Download Tracking in December, and the aggregate data already highlights some interesting trends.

Free applications have an average conversion rate of 10 percent, significantly higher than the average 1 percent conversion rate for paid applications.

Games generally have higher conversion rates than other categories of applications, up to a 100 percent improvement over non-game applications at similar price points.

The App Store is an effective distribution platform for free applications.

The average acquisition cost for free applications is under $1.00, significantly less than average application download costs on the PC Web.

"AdMob is the first to make this valuable link exchange service available to application developers," Ms. Leverich said. "Starting today, applications developers in AdMob's network can allocate a portion of their ad inventory to the exchange and begin helping each other drive downloads."