"AT&T appears to be the latest company to use its perceived power over the conduit to manipulate the message. Stanford computer science and legal lecturer Jonathan Mayer recently visited the Dulles airport in DC, and found AT&T's Wi-Fi hotspots pushing a number of pop up ads, overlaying themselves on browser content:
"AT&T has an (understandable) incentive to seek consumer-side income from its free wifi service, but this model of advertising injection is particularly unsavory. Among other drawbacks: It exposes much of the user’s browsing activity to an undisclosed and untrusted business. It clutters the user’s web browsing experience. It tarnishes carefully crafted online brands and content, especially because the ads are not clearly marked as part of the hotspot service. And it introduces security and breakage risks, since website developers generally don’t plan for extra scripts and layout elements.""