Heads-up, locals: China's Mobile Unicom and Telecom carriers are building a city-wide public WiFi network across Beijing. Residents will enjoy free 2Mbps internet for up to three years, if they sign up to the "My Beijing" service. Like most things that are gratis, there's a catch: you have to submit your phone number in exchange for access. Privacy enthusiasts aren't thrilled at the idea, (you know, since it's backed by the Government ), though a representative said that the numbers would only be used for "identity authentication" -- insinuating that they would only be tracing individuals whose online activity might " endanger social security. " High-minded privacy concerns aside, there's the very real danger of phones being bombarded with spam, not to mention what happens when the three year trial period expires -- users of the service could get stung with exorbitant costs to feed a public WiFi addiction.