The New York Times > Technology > Young Cell Users Rack Up Debt, a Message at a Time: "In the last two years, text messages - which cell carriers generally limit to 160 characters - have become a rage among teenagers, who embrace the technology as yet another way to escape a boring class or stay in touch with friends.
But text-messaging, or texting for short, has a downside. It can be expensive. Although phone companies offer relatively inexpensive packages - like Verizon Wireless's $9.99 for 1,000 messages a month - industry experts say that carriers sometimes fail to draw customers' attention to the cost-saving deals, and that customers themselves, especially young people, often exceed the number of messages allowed. In those cases, sending a text message usually costs 10 cents; the cost of receiving one ranges from 2 to 10 cents."
This and similar pricing/usage discontinuities on the data side are major inhibitors to broader wireless beyond-phone usage. Very counterproductive for the service providers, especially given the infinitesimal marginal cost for supplying the services.