"I suddenly felt like I was being followed, like you're in a dark alley," Mario recalls.

Experts say he's right. Consumers are quietly being followed, even targeted, when they browse online. This specialized software let's you see for yourself how you're being tracked while you surf the web.

The Federal Trade Commission is pushing to give consumers greater control by creating a 'Do Not Track' system. It's goal: To allow you to opt out of online tracking with the click of a button. Problem is, right now what 'Do Not Track' means is still being debated.

Edward Felten is with the FTC. He explains, "What the FTC has said that 'Do Not Track' should mean that information about where you go on the net is not collected by third parties with narrow exceptions for things like ensuring security."

But the FTC says some digital companies, want 'Do Not Track' to mean consumers can just opt out of receiving targeted ads, but not out of data collection.

"If your business model depends on tracking people online then obviously you'd like that to be able to continue," Felton says.

Linda Woolley with the Direct Marketing Association says it has to collect some anonymous data to help improve how the web works, and also use it for analytics and market research. "That's not for targeting, it's for if you're a rent a car company and you're getting a lot of clicks from a particular area you might want to open up a new rental car agency in that area."

The Digital Advertising Alliance, or DAA, recently unveiled its 'self regulated' opt out program. You just click on a little icon on behaviorally targeted ads and you can choose not to get them. Some web browsers offer new privacy settings which signal to companies you don't want to be tracked.

Mario's giving it a try. He says,