No sooner has iAd launched than Apple has begun enforcing ground rules for developers looking to incorporate it into their titles.

Its target – delivered via a message on the news section of Apple's iPhone developer centre - is preparing developers for what happens when an ad slot fails to fill.

It's a big issue for iAd, at least in the early days, as it's likely to be characterised by more demand for ads than inventory to fill them.

Should this happen, blank banners containing nothing won't be tolerated, with Apple sternly warning that any apps that don't have a fail-safe will be "returned to you by the App Review Team for modification before it can be posted to the App Store".

No room for error

"If you have dedicated a section of your app for an iAd, it's important to incorporate a banner view delegate that will handle common events, including errors," Apple says in the entry.

"Having the proper delegate to handle errors maintains the visual experience customers have with ads in your app by preventing a blank banner from being displayed when ads are not available."

Such strict measures will ensure  consumers aren't faced with an ad network that appears faulty. Keen to make sure iAd retains its initial high regard, Apple believes some visual stimuli is better than nothing at all.

You can read the entry in full in Apple's App Store submission tips section.

[source: Apple]