Wi-Fi Networking News points out that California Wi-Fi hotspot company MetroFi has crunched the numbers, and has decided to migrate from a monthly fee system, to free ad-driven service. The company offers mobile Wi-Fi, or allows home users to BYOB (bring your own bridge) for service. "At roughly $20 per month for unlimited usage, a good percentage of that had to be devoted to the expensive tasks of billing and marketing," says Fleishman. "Having ten times the users bringing in an average of 50 cents a month each in advertising should cover increased capital and recurring expenses while reducing staffing requirements."