That's an interesting idea, as long as O2 is really using the customer feedback. The German carrier has just updated it's "Mehr Netz" (more network) app for Android smartphones which allows customers to report network problems back to O2 Germany. During the recent years, O2 Germany put a lot of money and effort into the network roll-out and stabilization and O2 called this initiative "Mehr Netz". Therefore, O2 has given its Android app the same name since the one and only task is to give customers a backchannel. O2's Mehr Netz app allows to report for dedicated problems, for instance reception problems, slow data connection, etc. and customers can either add the location or get it automatically located.
Furthermore, customers can let O2 know under which circumstances the problem occurred (in-house, in trains or cars, etc.) and allows customers to add a comments to further describe the problem. As soon as network reception is available again, the app automatically reports back the problem the customer faced with O2's 2G or 3G network.
Using its customer base to get network feedback is an interesting idea to improve a wireless network quality and it might really help to fix the one or the other problem a carrier can't be aware of.
O2 Germany's Mehr Netz app requires Android 1.6 or higher and is available in German only.
Cheers ~ Arne