Announced alongside iOS 4 last year, Apple's iAd program is an attempt to shake up the mobile advertising business with more compelling ads that should theoretically lead to higher ad engagement and higher revenues for developers. According to the Wall Street Journal, not all the pieces of that puzzle have completely fit into place. Apple is apparently softening its stance towards advertisers by offering lower minimum ad buys of $400,000 (down from the original high of $1 million), capping per-tap costs, and even giving campus tours to ad executives. Meanwhile, the WSJ reports, iAd revenues for developers don't seem to have met expectations.

The reported changes come as Google reported $2.5 billion in yearly revenue off of mobile ads, which run on multiple platforms. Apple's iAds, of course, only run on iOS devices and so face competition both from the larger marketshare of Android and from Google itself on Apple's own products. Last month, Apple released a new version of iAd producer to help developers create compelling HTML5-based ads for iOS.

It looks as though iAd hasn't made a big impact on the mobile advertising industry, but hopefully the changes will at least help make an impact on developer's pocketbooks. With the average iOS app price sitting at around $2.00, every little bit helps.