Privacy experts say they are concerned about dozens of websites where children can play games — and are encouraged to share information about themselves and their families with market research firms.

"A lot of people will look at it and think, oh it's just a playground … but in actual fact these sites are much more," said University of Ottawa professor Valerie Steeves, who researches privacy issues related to technology.

"They are really market research laboratories that use the child's play so they can learn more about that demographic."

According to a study by the Ottawa-based Media Awareness Network, more than half of the top 50 websites children said they visit are commercial sites such as NeoPets and CosmoGirl.

The group's project manager Catherine Peirce said Monday she expects that trend has continued or even grown since the Young Canadians in a Wired World study was conducted in 2005.

On one such site, called Neopets, children can create a cute cartoon pet, dress it up, play games and download files such as screensavers and music — but first they must provide their date of birth, gender and location.

Peirce, the mother of five school-age children, said that's not unusual — her group's study found 90 per cent of the top 50 websites chosen by kids asked visitors to submit personal information. And 94 per cent collected additional information through contests and surveys.

For example, Peirce said she saw one online game in the past year featuring Lucky Charms cereal.

After playing the game, if the children were old enough, they were invited to fill out a survey.

"And that survey asks you questions like, what's your parent's income level, and what are your favourite cereals," she said.

Some sites such as NeoPets ask children to read a privacy policy and ensure their parents consent to an online agreement before registering for the site. But Peirce said the sites have no way of ensuring that parents did consent, and most privacy policies are written in complex language that children can't understand.

Meanwhile, she said, many parents aren't necessarily aware of what their children are doing online.

"Parents are more connected, but there is still a disconnect between the tech-savvy kids and what their parents know."

The federal government is considering changes to its privacy laws, but it's not clear if any new limits will be placed on commercial sites aimed at children.