I was reading this news article today that talked about a person who had racked up a cell phone bill of $85,000. You can read the story at http://www.financialpost.com/story.html?id=166511
In general, the person used his cell phone to acquire Internet access for his computer as he assumed his $10 a month unlimited browser plan would cover that. I believe the terminology for that would be data tethering where people connect their phones to a computer to gain access to the Internet when they are say on the road. Here in Canada at least it can be quite expensive and it is definitely not the same thing as having an unlimited browser service for your phone.
This is one of those situations where I am on the fence on whether or not the person should rightfully pay for the bill as the provider didnâ€™t mislead its service in anyway. Like always, ask a lot of questions when it comes to service contracts if you are not sure.