Seymour "Sy" Goodman, an expert on information security at Georgia Tech's Sam Nunn School of International Affairs, does not have a Facebook page.
Goodman knows the risks of spreading personal news and information on the Internet probably as well as anybody, but even he does not know as much as he should. The field is too vast and it changes too quickly.
"I am going to tell (people) what kind of risks they have out there and what they can do to mitigate those risks, and it's not the type of thing I would have said to them 10 years ago. ... People can't keep up with it. I can't keep up with it," he said.
And why does an Internet security expert not have a Facebook page? In a word, privacy. It's what we hold so dearly yet give away in the public forums of cyberspace, where others can take advantage of it.
"You don't provide Facebook with a penny," Goodman said. "So how does Facebook make its money? You are their product." Well, not you, but everything you post. Pictures. Family names. Where you travel. Pictures of things you like.
Facebook, Google and all of those handy apps on your smartphone collect your data and locations and use information to figure out how to sell you stuff. Or some unscrupulous firms may sell your information to others. But however your information gets out there, there are people trying to figure out how to use it to their advantage, legal or not.
Online theft and fraud is a growing problem. Recent numbers from the Federal Trade Commission's Consumer Sentinel Network say Georgia in 2011 had the second-highest theft of identities per capita. Florida was No. 1.
But it does not take a thief to cause damage. Friends or employers see something floating out there on the Internet, and bad things can happen.
Like the Barrow County, Ga., teacher pressured to resign in 2011 after Facebook pictures showed her on vacation with glasses of wine and mugs of beer.
"Each of us needs to give some thought to how to handle that risk. There are many ways available to us, although nothing guarantees security, and we all need to think about what we might lose if some things go wrong, and act with that in mind," Goodman wrote.
"I am going to explain to them why they are vulnerable and give them a sense of what little they can do about it."
Explore further: Facebook abuses 'quasi-monopoly' on user data, EU lawmaker says