You must have seen those ads – “What an Idea! Sirji!!” of Abhishek Bachhan and how having a generic phone number ensures that all problems due to differences in caste, sect, religion are removed. Novel way to target and position yourself to the masses indeed.
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. 
. 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.
