Comcast uses javascript ad injection on company's wi-fi network

In the past few years, we have seen a number of internet service providers (ISP’s), hotels and stores run into trouble when they used deep packet inspection and ad injection to force advertisements onto users accessing their system without the customers knowledge.

Now, as Ars Technica notes, Comcast is using Javascript injection to put ads into any websites visited by users connected to one of its 3.5 million publicly accessible Wi-Fi hotspots across the US. In typical PR fashion, Comcast tells Ars Technica the pop up’s are a “courtesy.”

“We think it’s a courtesy, and it helps address some concerns that people might not be absolutely sure they’re on a hotspot from Comcast.” – Comcast spokesman Charlie Douglas

It is a “courtesy” that was only admitted by Comcasty after a startup founder realized that he was seeing Comcast ads while on a non-Comcast web-site.

The Comcast advertising campaign came to Ars’ attention after Ryan Singel, the co-founder of startup Contextly, was reading Mediagazer at a café in the North Beach neighborhood of San Francisco on Labor Day. A small red advertisement saying “XFINITY WiFi Peppy” scooted across the bottom of the Mediagazer page and disappeared into the ether. It happened a few times, he said. Singel took screen shots of the advertisement loading and as it appeared on his screen. He captured some code, too. – Ars Technica

As Karl Bode notes at DSLReports, the ads are only injected via Comcast’s traditional hotspots, not user home routers that have been recently modified to offer public Wi-Fi access.