When Apple introduced iOS 4 for the iPhone and iPod touch (it will also be supported on the iPad in the very near future), the company also introduced a new advertising system that allows apps to host advertising.

This may be a great feature or a big headache, depending on your point of view. There's no question it will allow app authors to create unique applications and release them at little or no cost to end users; an author's revenue for a particular app would come from the advertising stream instead.

But in addition to saving you money, the feature may turn your mobile device into a walking billboard.

If you're leaning more toward headache than great feature, Apple provides an opt-out option. You can disable some iAd features, specifically the interest-based ads, which are presented based on data collected by your mobile device. For instance, you may see targeted ads based on information about your download activity, purchases, or other personal information. Download an app to find out what movies are playing in town, and you may start seeing iAds from movie studios.

Disable iAd Data Collection

Turning off the iAd data collection feature is pretty simple. Using your supported iOS 4 device, browse to the following location:

http://oo.apple.com

You should see a "You have successfully opted out" message.

A few notes about this opt-out option. It only works for devices running iOS 4. The opt-out is device specific, not user specific. If you have multiple iPhones or other mobile devices, you will need to use each one to access the above URL to opt-out.

Finally, this option doesn't completely disable iAds; it only prevents the data collection that would have been used to personalize the ads you see.