Poor Representative Anthony Weiner. He just learned a very tough lesson: Your online activities remain truly your own for only as long as they are still in your head and not in a digital form. What you do online counts. What you say in private matters, what you shared with others can be found. Every single action we take online leaves a trail of debris that could eventually pile up and then topple over on top of us.

Our digital age has come with enormous benefits and some very real consequences. We can share endlessly through email, voice messages, texting, and social networks. The fact that these avenues exist has only encouraged more sharing; certainly more than most people did before with random strangers. Yet, for all the public sharing, there is a steady undercurrent of private digital interaction, and this is where the real trouble lies.

I'd say that roughly 10 percent of my tweets are conducted on Twitter's Direct Message channel. This is Twitter's private channel where you can share a 140-character post (including, potentially, a link) with one person. You can only "DM" someone if they are already following you, which means they've at least opted in for this possibility. Representative Weiner knows this. He was using this pipeline to send some rather highly personal Tweets to a number of young women. I guess it was like flirting, but ratcheted up a good bit with the inclusion of sometimes salacious language and pictures. The content of these "private" tweets does not interest me. What happened to those tweets, though, does.

What Congressman Weiner failed to realize is what I fear many online participants still do not get: Once you put something in digital form, it can grow legs and run (not walk) out of your control. You're not typing words on a keyboard; you're loading a slingshot full of electrons and letting go. And those ones and zeros bounce. They may hit Twitter or Facebook and stay there briefly, but like a sling building up potential energy as you pull it taut, they're just getting ready to take flight again.

Put simply, you have little to no control over your digital bits. Those DMs and Facebook posts are friable digital debris, just waiting to take flight. And it happens so simply. For Weiner, the DM conversations were two-way, which means the recipient managed to collect multiple sexually charged tweets and images. Did the recipient know at the time that they might use those messages against the congressman? I have no idea. What matters is that they could and did. There is nothing fundamentally secure about Twitter's Direct Messages. I'm staring at a bunch of them in my TweetDeck DM column right now. I can take any one of them and copy and paste it into a document for posterity. I can also email the tweet to myself or others. If there's a link to a photo in the "private" message, that goes along for the ride, too.

Obviously, your digital data problem extends well beyond Twitter. To understand the nature of all this digital debris, we need to understand how digital data works. Digital content is, by its very nature, super easy to store and retrieve. It takes up very little space (even video) and is easy to duplicate; plus digital content loses absolutely nothing in the process. A duplicate file is exact. A duplicate image is the same. Copying and pasting a tweet, Facebook post, or text message changes nothing about the original.

Digital is also persistent. It's almost as if it fights against deletion. Most of us delete e-mail, documents and image files every day. Or perhaps we simply move them to another location. Let's get this straight. You are not actually deleting or moving anything. Telling your computer, phone, tablet or even social networks to delete a file or post only means that, one, you can no longer see the post or, two, the space that data originally occupied is available for a new data. Considering the size of today's hard drives, it's unlikely much of anything gets written over, which means that, with the right tools, it can be retrievedby almost anyone.

If you work in a company dealing with financial information, all your email is saved somewhereyes, even the deleted stuff. You smartphone texts probably still reside somewhere in the recesses of your smartphone memory and, without a doubt, on the cellular service provider's servers that helped deliver the texts back and forth.

When it's time to throw out your home computer, I often advise people to either remove the hard drive and save it or to drive a nail through it to make sure no one else can start perusing your digital debris. Social networks, though, present a more difficult problem. You do not control the hard drives (read "servers") where your actually posts and images reside. Facebook has them. Twitter has them. Twitpic has them. TwitVid has them. yFrog has them. And they have all of them. You can request, though, that these services remove all of your posts and images.

But that won't solve your digital debris problem. As I said earlier, what you shared with others online, even in private, could haunt you later because this digital debris now resides on someone else's computer. Perhaps they don't want to share your private tweet or an illicit Facebook post, but what if they viewed and saved the image? Now it's on their hard drive—more digital debris floating out in space.

I know, I sound like the voice of doom, like we're all one keystroke away from digital disaster. On the other hand, we all are, aren't we?