By Rory Cellan-Jones
Technology correspondent, BBC News
Sir Tim Berners-Lee has fears over the future of the internet
The creator of the web has said consumers need to be protected against systems which can track their activity on the internet.
Sir Tim Berners-Lee told BBC News he would change his internet provider if it introduced such a system.
Plans by leading internet providers to use Phorm, a company which tracks web activity to create personalised adverts, have sparked controversy.
Sir Tim said he did not want his ISP to track which websites he visited.
"I want to know if I look up a whole lot of books about some form of cancer that that's not going to get to my insurance company and I'm going to find my insurance premium is going to go up by 5% because they've figured I'm looking at those books," he said.
Sir Tim said his data and web history belonged to him.
I think consumers rights in this are very important - we haven't seen the results of these systems being used
He said: "It's mine - you can't have it. If you want to use it for something, then you have to negotiate with me. I have to agree, I have to understand what I'm getting in return."
Phorm has said its system offers security benefits which will warn users about potential phishing sites - websites which attempt to con users into handing over personal data.
Kent Ertugrul, chief executive, of Phorm, told BBC News: "We have not had the chance to describe to Tim Berners-Lee how the system works and we look forward to doing that.
"We believe Phorm makes the internet a more vibrant and interesting place. Phorm protects personal privacy and unlike the hundreds of other cookies on your PC, it comes with an on/off switch."
The advertising system created by Phorm highlights a growing trend for online advertising tools - using personal data and web habits to target advertising.
Social network Facebook was widely criticised when it attempted to introduce an ad system, called Beacon, which leveraged people's habits on and off the site in order to provide personal ads.
The company was forced to give customers a universal opt out after negative coverage in the media.
Sir Tim Berners-Lee talks about the future of the internet
Sir Tim added: "I myself feel that it is very important that my ISP supplies internet to my house like the water company supplies water to my house. It supplies connectivity with no strings attached. My ISP doesn't control which websites I go to, it doesn't monitor which websites I go to."
Talk Talk has said its customers would have to opt in to use Phorm, while the two other companies which have signed up - BT and Virgin - are still considering both opt in or opt out options.
Sir Tim said he supported an opt-in system.
He's the greatest technological pioneer Britain has produced over the last 30 years
BBC News Technology correspondent Rory Cellan-Jones on interviewing Tim Berners-Lee
"I think consumers rights in this are very important. We haven't seen the results of these systems being used."
Privacy campaigners have questioned the legality of ISPs intercepting their customers' web-surfing habits.
But the Home Office in the UK has drawn up guidance which suggests the ISPs will conform with the law if customers have given consent.
Sir Tim also said the spread of social networks like Facebook and MySpace was a good example of increasing involvement in the web. But he had a warning for young people about putting personal data on these sites.
We should look out for snags in the future - things can change so fast on the internet
Sir Tim Berners-Lee
"Imagine that everything you are typing is being read by the person you are applying to for your first job. Imagine that it's all going to be seen by your parents and your grandparents and your grandchildren as well."
But he said he had tried out several of the sites, and thought they might in the end be even more popular with the elderly than with young people.
Sir Tim was on a short visit to Britain from his base at MIT in Boston, during which he met government ministers, academics and major corporations, to promote a new subject, Web Science.
This is a multi-disciplinary effort to study the web and try to guide its future. Sir Tim explained that there were now more web pages than there are neurons in the human brain, yet the shape and growth of the web were still not properly understood.
"We should look out for snags in the future," he said, pointing to the way email had been swamped by spam as an example of how things could go wrong. "Things can change so fast on the internet."
But he promised that what web scientists would produce over the coming years "will blow our minds".
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