Sprint kills unlimited data for mobile broadband devices

With the latest move from Sprint, the end of smartphone unlimited data is inching a lot closer.

Where there's smoke, there's fire, and right now Sprint is throwing the kindling on the blaze that will eventually toast its smartphone unlimited data plans.

Sprint announced on Thursday that it is killing its unlimited 3G and 4G data for mobile broadband devices. The end comes on October 31st, after which users of the services will be limited to a monthly 3GB, 5GB, or 10GB, depending on their plans. Running past the limit will cost a startling five cents per megabyte.

"If you have a mobile broadband device such as a tablet, netbook, notebook, USB card, connection card or Mobile Hotspot device, effective beginning with your next bill following notification, your on-network monthly data allowance will no longer include unlimited 4G," Sprint's says. Sprint isn't even grandfathering in current subscribers, which certainly adds to the sting.

The move doesn't affect smartphones, but if Sprint's recent decisions are any indication, smartphone unlimited data will meet its end soon enough. Considering that one of the company's biggest selling points is its unlimited data, it's unlikely that customers will stick around when that eventually happens. Once unlimited data jumps ship, so does any remnant of Sprint's competitive advantage.