"On the Internet, no one knows you're a dog."

That oft-cited Internet adage, courtesy of an early 1990s New Yorker cartoon, could use an update: They may not know you're a dog, but they'll know if you've browsed kibble, collars and pet beds. And advertisers will make sure you see more of those items online with personally targeted ads.

Thanks to multiplying and ever-evolving technology, you're being tracked all over the Internet. What you browse and click paints a portrait of you that advertisers mine in order to put ads in front of the right consumers.

Creepy or convenient? That depends.

"People have kind of mixed views about it," said Jisu Huh, an associate professor who teaches advertising at the University of Minnesota. "The advertising is definitely more personally relevant, but at the same time it can trigger consumers' privacy concerns."

That personal relevance is key, according to Huh's research. Increase it, and the privacy concerns go down.

But all this tracking can still be problematic because there's no easy way to opt out, said Cooper Quintin of the Electronic Frontier Foundation.

"People should at least have that option to legitimately not be tracked," he said. "You know that you're being watched. When we know we're being surveilled, we sort of internalize this. We stop doing things we would normally do because you're no longer ever in a private space."

Craig Bryan, a "recovering ad guy" who now teaches advertising and communications at University of St. Thomas, is among the sometimes unnerved Internet users.

"There's no damage done, I just don't feel very good about it," he said. "It's invading my privacy. I don't want these people to know what I've been browsing."

Yet when he queried his undergraduate students in class, they weren't so bothered.

"Without exception they said, 'I like it. It works for me,' " Bryan said.

Why? They said the ads are time savers, a resource.

That lines up with the ad industry's pitch: "Consumers click on interest-based advertising two times as much as they do generic ads," said Lou Mastria, executive director of the Digital Advertising Alliance. "There's advertiser benefits in that and there's consumer convenience in that."

Still, Steve Wallace, vice president of the Ad Fed MN, said privacy concerns are important to consider going forward. Even he uses browser plug-ins to "track the trackers" sometimes.

"There's an illusion that what you are doing is anonymous, and it's not," he said.

Tell that to the dog.

Katie Humphrey • 612-673-4758