Say you had a lapse of good judgment in your youth, hung out with some Communist Party members and shared some photos of you and your new pals with your Facebook friends.

Now say you're older, and you choose to run for office, and you want to get rid of any incriminating photos or information out there about you — like maybe that online petition you signed advocating the legalization of marijuana. You delete everything from your Facebook page, and you should be good, right?

Slight problem. That picture of you and the guys with the hammers and the sickles is probably still out there, somewhere. And it won't go away.

Share it once, share it for life. That's the conundrum when it comes to people expecting privacy after they share photos or other information with hundreds of friends on Facebook — or any other social networking site, for that matter.

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"If you send something to 400 people and publish it, it's publishing -- just the way the Wall Street Journal is. I think people don't realize it's publishing ... it's not private anymore," said Kara Swisher, co-executive editor of the All Things Digital Web site and a Wall Street Journal columnist who has covered digital issues for more than 10 years.

"Most people do share it with 400 people, not two or three. The question is: Should you share, can you have the expectation of privacy? And you can't."

That's also the message Facebook was trying to get out when it altered (or "clarified") its terms of service, which users agree to when they sign on to the site.

Before Feb. 4, the license you grant Facebook that allows it to share your content and information with third parties expired when you terminated your account.

The new terms removed that "kill switch." You could delete your information on your own page, but Facebook retained the right to keep other copies in the system indefinitely, since you presumably shared some of it with other users.

Amid an outpouring of criticism from privacy advocates and Facebook users over the change, the Electronic Information Privacy Center, based in Washington, D.C., was ready to file a complaint against the social-networking site Wednesday morning.

But on Tuesday night, Facebook told EPIC that it was reverting to its old terms of service, at least for while.

"We said, 'That was a good decision,'" EPIC Executive Director Marc Rotenberg told FOXNews.com on Wednesday.

Many Facebook users seem all too happy to post their day-to-day activities — what flavor coffee they're drinking, what time they put their kids to bed — for all the world to see. But it appears they don't want to lose control of their content.

Critics of Facebook's move said the rules can't be changed in mid-stream, especially without full disclosure.

"Facebook, and other online companies, need to be transparent in their business practices and let consumers know exactly what personal information will be retained and what it will be used for," said Randy Skoglund, executive director of the Washington, D.C.-based Americans for Technology Leadership. "To remove an important clause once users have already signed up gives consumers no real choice in how their information is used."

But some may ask — didn't you already make that decision when you shared your life's details and photos with your 400 Facebook friends, who then shared your personal news with their 400 Facebook friends, and so on? Shouldn't you expect to lose some control over what happens to your photos?

It doesn't take a rocket scientist to realize that anything you post online is hardly private, and it could come back to bite you at a most inconvenient time.

"You would think that it would be absolutely obvious at this point, given the amount of media and general societal chatter about that fact, but it still amazes me that there's surprise around this issue," said Lisa Sotto, head of the privacy and information management practice at Hunton & Williams, a New York law firm.

"Clearly these are sites that use data very robustly and store extremely sensitive data, and that should be absolutely obvious to any user."

EPIC and other privacy advocates say users should have the right to control how their content is used, but they acknowledge that once you share, it's out of your hands.

"You should have the right to remove the information. I don't think you can prevent others from recording it if you made it public, but I don't think Facebook should stop you from removing information. ... It's important that people can make these choices," Rotenberg said.

"I don't think we can assume that information will be protected, but I do think we need to make clear in the collection and use of information that there are clear rules" for how it can be used by the site, he added.

Facebook is crafting new terms of service, and it's soliciting input from users this time. And while it promises not to sell user information for profit or for advertising purposes, "we do need certain licenses in order to facilitate the sharing of your content through our service," said spokesman Barry Schnitt.

Swisher, who met with Facebook executives Wednesday, said they had no intention of selling anyone's information — "that's like a canard from all the privacy advocates" — but they realize they went about the whole thing the wrong way.

"They're still leaving the door open to reconsider it, and I suspect, from a public-relations standpoint, they won't go back," said Paul Stephens, director of policy and advocacy at the Privacy Rights Clearinghouse, based in San Diego.

Where Facebook's policies — or any other Web site's — on how content is used are concerned, be sure to read what Sotto describes as the "legal gobbledygook."

And if you're thinking of a career in government service, or with any other employer who will do even a casual background check, think twice about who your "friends" are on the Web. You never know when your associations may come back to haunt you.