Tracking user activity as a way of serving up ads is now common across pretty much the entirety of the web, but knowingly tracking children remains illegal, and four massive media companies have just paid the price for engaging in such activities.

New York Attorney General Eric Schneiderman announced that a settlement has been reached with Hasbro, JumpStart Games, Mattel and Viacom over the tracking and collection of personal information of children under the age of 13 - a violation of the Children's Online Privacy Protection Act (COPPA).

The two-year investigation found websites owned by the companies that are specifically aimed at children, such as those for My Little Pony, Neopets, Barbie, Dora the Explorer, Hot Wheels, and Nickelodeon, allowed third-party trackers.

All the organizations will now have to monitor for third-party trackers, conduct regular scans and vet vendors' data collection practices to ensure they comply with COPPA.

Additionally, JumpStart Games, Mattel, and Viacom will have to pay a collective total of $835,000 in fines. Hasbro avoided the financial penalty as its actions were found to be less severe and it is a member of the FTC's Safe Harbor program, which indicates a site complies with COPPA.

"We used to worry about our children wandering into bad neighborhoods," said Schneiderman. "Now our children live online, and we have to police the internet the same way we police the streets."

While the fine isn't going to have much of an effect on such large firms, it at least shows that authorities are taking a stand against companies flouting the rules when it comes to monitoring the online activities of kids.