PHILADELPHIA  Brandon Dilbeck, 20, a student at the University of Washington, was complaining recently on his blog, Brandon Notices, about Comcast’s practice of posting ads in its on-screen programming guide.

He assumed he was writing for his own benefit. “It feels like nobody ever really reads my blog,” he said. “Nobody has left a comment in months.”

Shortly afterward, he received an e-mail message from Comcast, thanking him for the feedback and adding that it was working on a new interactive guide that might “illuminate the issues that you are currently experiencing.”

Mr. Dilbeck found it all a bit creepy. “The rest of his e-mail may as well have read, ‘Big Brother is watching you,’ ” he said.