Comcast’s decision to inject data into websites raises security concerns and arguably cuts to the core of the ongoing net neutrality debate. A Comcast spokesman told Ars the program began months ago. One facet of it is designed to alert consumers that they are connected to Comcast’s Xfinity service. Other ads remind Web surfers to download Xfinity apps, Comcast spokesman Charlie Douglas told Ars in telephone interviews. The advertisements may appear about every seven minutes or so, he said, and they last for just seconds before trailing away. Douglas said the advertising campaign only applies to Xfinity’s publicly available Wi-Fi hot spots that dot the landscape.