iOS devices (iPhone, iPod Touch, iPad) come with parental controls. Android OS, interestingly, does not. This is rarely discussed .
Parental controls should be important to parents with children who, by age or disability, are particularly vulnerable to exploitation and injury. They are, of course, also important for cultural reasons.
Even though Apple's iOS includes parental controls, they are very weak. Disabling Safari does not disable embedded browsers, and many, many applications embed WebKit browsers. It is not hard, for example, to navigate from the NYT's iPhone App to Google's image search.
Apple has an ad platform too. It's called iAd. It's not based on WebKit, it's an Objective C (Cocoa) framework. This morning I viewed the Tron iAd featured on the New York Times iPhone app. The Ad was ... impressive.
Clearly Apple's iAds have a high barrier to entry. Perhaps not as high as a television or major print advertisement, but much higher than traditional web advertising. The one I saw was essentially an application. iAds will need to scope their material to the parental control rating of the container application.
The Tron Ad did not have an obvious WebKit escape. Whether one exists or not, it is clear that iAds can achieve their goals within a fully constrained environment. Apple's iAds are Parental Control friendly, Google's Mobile Ads are not. If Apple were to enable a Parental Controls block for embedded browsers, they'd break Google's Ad Platform on iOS devices. Children are an important advertising target. This should be interesting.
 Another unmentionable is that iOS comes with FairPlay DRM (digital rights management), Android OS lacks a DRM standard. Even Gruber, a giant of fan blogs, does not seem to get this. FairPlay is worth billions to the iOS App market.