By this rate of depreciation, I thought it (no. of users) would have gone negative years ago :-D

In India, SMS was free of charge too. Most telcos still have it. Some have/had offers like 100 msgs per day or 3000 per month free. Well maybe understandable since there are MANY subscribers. When I came to US, I was absolutely shocked to see that subscribers are charged for incoming messages (mine charges about 15c). How backward!! Customers 'voluntarily' accept n enter into this rip-off here.