Come to the streets of Mumbai, there you see a different picture. Idea ads have celebrities declaring proudly, that they have an Idea Mumbai No., and that makes them a Mumbaikar. The niche is well defined and it does have an appeal to it. I consider myself a Mumbaikar, but would I go to the extent of getting an Idea Mumbai No. :-P. But it’s a good ad nonetheless.
So in one case, Idea is seen generalizing their service offering, whereas in the other, the same offering (viz., the phone number that you get) is a way of defining and segregating the masses. Interesting, wouldn’t you say? Kind of like Glocalisation.