Well, Google already does this with its Android platform. The information is typically not used to track you per se, but the device and services that are being accessed on it. The feedback generated by this information helps developers and third-party companies improve the performance and capabilities of their apps. At least, in theory.
The new privacy terms must be agreed to before users can update or download apps from the iPhone App Store. Most users will click the "accept" button without reading the new terms. The only way to avoid agreeing to the terms would be to stop using iTunes do download applications. That's not a realistic alternative.
Here's the new clause in its entirety so you can see what Apple is saying:
As Apple notes, the information isn't being tied to any specific end users and can't be used to discover their identity directly. Many of the applications that are offered to the iPhone are location-enabled. They are required to ask the user if the user wants the application to access their location data before it can do so.
To provide location-based services on Apple products, Apple and our partners and licensees may collect, use, and share precise location data, including the real-time geographic location of your Apple computer or device. This location data is collected anonymously in a form that does not personally identify you and is used by Apple and our partners and licensees to provide and improve location-based products and services. For example, we may share geographic location with application providers when you opt in to their location services.
Some location-based services offered by Apple, such as the MobileMe "Find My iPhone" feature, require your personal information for the feature to work.
That means if you use Foursquare, for example, and allow it to collect location data while you use it, you have opted in and shouldn't raise too much fuss about how Foursquare uses that data after the fact.
Google Maps wouldn't be very useful from your mobile phone if the phone couldn't tell Google Maps where you are.
You get the idea.