A guy who used a peer-to-peer file-sharing system inadvertently publicized a lot more on his hard drive than music files, WTOC 11 reports:

Don Bodiker uses a popular file sharing program to swap music and other information over the internet. He also uses his computer to prepare his taxes.

He never thought the two had anything to do with each other, until he got a call. “I had no idea who he was or what he was. I just thought he was a typical telemarketer,” Bodiker said of the call. “And he wanted to inform me that my tax returns were being posted out on the internet. I was very skeptical but he then proceeded to tell me some very specific details about my tax return.”

File sharing software allows you to download files stored in certain shared folders on other users’ computers. The flipside is they can also download files from your shared folder. There’s a folder on their computer the Bodikers use store the music files they wanted to share. What they didn’t realize is that their tax return software saved their returns in the very same place.

“Oh my God, I thought everybody and anybody knows exactly what my social security number is, my address, you know, anything that I had that was pertinent on there that could be used as an identity theft process,” said Bodiker.

And he’s not alone. A simple search on the file sharing network for the word “tax” turned up hundreds of returns. “It’s made me more aware of the possibilities of programs that you attach to your computer,” said Bodiker. “Ultimately, if you don’t have to keep it on your computer, make a hard copy, and file it away. And that’s always the best thing.”

Don’t believe it? Download LimeWire and type in “federal return” or “1040″ and see what pops up. I did it, and within a few minutes, I had access to scores of tax returns that included names, addresses, social security numbers, and bank account numbers.

Among hundreds of tax returns I saw, here are three I downloaded (note: sensitive information has been redacted): 1, 2, 3.

It’s not just tax returns. During the past nine months, Rick Wallace, editor of the See What You Share blog, has used P2P to obtain all kinds of confidential government reports, including more than 25 classified military documents.

Don Bodiker’s experience is a much-needed reminder for ordinary citizens and military personnel alike who use P2P: Be careful what you share. You never know who’s snooping around.