Late last year, AT&T, Sprint and T-Mobile together announced that they will no longer offer or support Premium SMS services (with Verizon following shortly after). Premium SMS supports things like ordering ring-tones, checking horoscopes and all sorts of other things I have never done. It also supports legions of spammers, shady SMS aggregators and 3rd parties who try to bill people a few dollars here and there and hope they get away with it. This service has been around for a long time and carriers love(d) it because they received a cut of each transaction. Lookout did a great blog post on how the whole process works (https://blog.lookout.com/blog/2012/10/03/avoid-premium-sms-scams/).