You learned sharing was good in kindergarten but sharing as an adult comes with some risks, especially if you don't know the law about 'peer to peer' sharing.

"You can go online and download some software onto your computer that connects you with a network of other users and you can share files with them," said Mary Engle, Federal Trade Commission.

For example, users can download songs off your computer, and you can search theirs. The Federal Trade Commission says the problem is that users may end up sharing more than they realize.

"We're concerned that consumers may accidentally share folders that contain private documents that they don't intend to share," said Engle.

And that can lead to identity theft.

The feds recently nabbed a man for using file sharing programs to steal tax forms and credit reports. They say he opened fake accounts and bilked people out of tens of thousands of dollars.

There have been other security breaches.

"…where employees will use laptops that they use in a company and then bring them home and children would install software and the files, which were taken out of the office, might be shared on a network," said Sam Berline of LimeWire.

How does it happen?

When you install the software, there's a designated folder where you save any files you download off the network. The problem: sometimes the folder is installed in a place such as 'my documents' where you store personal information.

"And you've got identity thieves who are searching these sites and what they find is lots of personal information like social security numbers, credit card information, financial information," said Engle.

The government is working with file sharing sites to improve privacy protections and says the industry is taking action. Including companies like LimeWire.

"The newer versions of LimeWire will prevent people from sharing file types that are most likely to have sensitive information," said Berlin.

Expert Nathan Good says some services allow you to close off your computer to other users, but it's frowned upon. He says the key to safety is to keep your shared files separate.

"Go to a location where you wouldn't inadvertently transfer personal information, create a folder called 'File Sharing' and then you can share that one and you should be okay," he said.

The Federal Trade Commission is working with the Department of Justice and Congress in monitoring file sharing services and identity theft.