Go to this Airtel SMS FAQ and click the Expand All button and scroll down a bit. One of the questions you’ll see is this (emphasis mine):
Q: I don’t like the content I am getting.
A: You can select your interests by logging on to the SMS2.0 website on http://www.sms2.in.
Note to Airtel: Provide user with the URL.
There are others like this on the page, which you can try and find if you are so inclined.
I just think it’s funny that the internal communication between a vendor and a client made it to a web page. Clearly, this was a feature that wasn’t supposed to be out there.
Note to Airtel: Remove the notes.