According to an article on AgencyFAQ,
The Do-Not-Call Registry being put in place for regulating unwanted marketing calls and SMSes may seem like a dampener for mobile marketing firms, but there is a new breed of companies that is actually counting on it. Affle is one of them. The London based mobile technology company collaborated with Bharti Airtel in June to bring its advertising platform SMS 2.0 to India. SMS 2.0 delivers relevant ads to subscribers in their message inbox.
Affle has introduced SMS 2.0 ads and the way it works is,
The way SMS 2.0 works is that your handset will be updated periodically throughout the day with ads that are cached and every time you go to text someone an ad will pop up. The cached ads that are updated via GPRS in the background are supposedly based on user relevance, which is said to be accurate approximately 75 percent of the time.