With Halloween around the corner, it’s time to get a jump on Internet haunting. I’m not talking about ghosts posting on message boards or mysterious noises in your hard drive. No, Internet haunting is a real phenomenon, though it’s perhaps not quite what you think.

Today, most students cast a significant and growing online shadow. We flood the world with e-mails. We post our profiles on the Facebook, Friendster or MySpace. We dither away the hours chatting through instant messengers. We keep blogs, maintain personal Web sites, share photos online, text each other all day and post grammatical train wrecks on discussion boards. And one day, we die.

So what happens to these online identities when we shuffle off this mortal coil? For a rare few individuals with extraordinary foresight, passwords are saved, records are kept and the task of dismantling their online existence falls to a relative. But for the vast majority of us, we live on. We haunt.

This sobering thought is apparently outside the ambit of acceptable party conversation. When I broached the topic at a barbeque last weekend, I was met with shocked silence. After a pause, one fellow asked me, jaw agape, “You … you’ve got dead Friendsters?” No, in fact, I do not. But I will someday, as will you. As flesh-and-blood humans, our ultimate mortality needs hardly to be driven home, but the digital world we inhabit is all too good at preserving exactly the impressions we make.

The stuff we post to the Internet can have a staggeringly long half-life. A grad school colleague recently uncovered an online personal ad from a professor we both know, dating back to the mid-90s. It was preserved and dutifully indexed by Google Groups. I’m guessing our would-be Romeo wouldn’t have hit “submit” so fast had he foreseen his own students chuckling a decade later. (To make matters worse, 10 long years yielded not one reply to his ad.)

This little anecdote emphasizes the surprising longevity of even our most casual online emissions. So yes, your own past can haunt you. But worse still, if you’re not careful, your entire digital present could linger on to haunt everyone else, forever.

In our society, it’s customary to speak well of the departed. Over the past few years, I’ve noticed that when a friend passes away, our instinct as students is apparently to visit their profile and pay homage by eulogizing in the testimonials area. This makes for some awkward maneuvering as we, suddenly somber, try to ignore our own earlier, teasing messages still staring up from the screen. Worse yet, while we wax lyrical about the merits of the deceased, we do so mere pixels below their now-irrevocable keg-stand photo, or a transcribed drunk-text they’d surely rather forget. One has to wince.

You’d think someone would have dealt with this — after all, people die all the time — and to some extent, they have. Friendster has an official policy wherein deceased members’ profiles can be converted to memorial pages. However, since this process requires that the user — presumably someone in possession of his password, not the deceased himself — log in and make it so, to date only a handful of people have actually exercised this option.

Leaning toward the macabre, a Web site titled MyLastEmail.com offers a service wherein, in exchange for an annual fee, five e-mails are stored and then released to loved ones upon your death. I’m not entirely sure what this is supposed to accomplish, since you could just as easily store such missives in hardcopy with a will; admittedly, your death-memos would then no longer arrive with a banner offering low-rate mortgage refinancing or enticing challenges to click the monkey and win an iPod. And seriously, if grandma can click that monkey through her tears, that alone is worth 30 bucks a year.

Is there a better solution? Rather than timidly releasing death e-mails from beyond the grave — a practice more likely to terrify than soothe the recipient — I hereby propose a posthumous legacy-scrubber. Like Victor the Cleaner in La Femme Nikita, this company could sanitize all your profiles, render them family-safe, and whitewash those pesky testimonials. We’ll post death notices to all your favorite message boards, retire your blog and put your best possible picture back on the Facebook. Shell out for our premium service, and we also promise not to spam people from your messenger account when you’re dead. It’s a pretty good deal, all told.

Fine, premature death is no place to turn a profit. But, all kidding aside, this really is an issue where an ounce of prevention can mean six feet of cure. I’m not suggesting we post solemn eulogies as Facebook profiles, or indeed live life as some morbid trudge toward our final day. But we might give some thought to storing our account information someplace, perhaps with instructions to address the most glaringly gauche beacons of our online existence. Otherwise, those compromising photos and inside jokes we deposit on the Facebook may well be our digital legacy. And that, my friends, is just poor form.

Michael Seringhaus is a fifth-year graduate student in molecular biophysics and biochemistry. His column appears on alternate Thursdays.