The man forced to marry a goat in Sudan. That bloke with a pea-plant growing in his lungs. The guy who threw a mouse onto a fire which then ran back into his house and burnt it down. We’ve all seen them. The zombie articles that rise from the dead again and again to top the most read lists of big news sites like the BBC. How does it happen, and what should we do about it?

The first thing to get out of the way is that there is something of a stigma about this content in the industry. We call ourselves “News” publishers for a reason. Our entire workflow is geared up to producing the next story and the next story and the next story. We seldom look back and reflect on things unless there is a convenient anniversary, birthday, marriage or death to hang them on. So lightweight stories like these popping up is often considered an annoyance. Something that doesn’t make our website look up-to-date.

But there is a flipside to that. Everything is new the first time you read it. What difference does it actually make to the BBC’s reputation if the burning mouse was from 2006 if you’ve never read it before? And the stories that tend to resurface in this way usually capture something brilliantly human – a quirk of fate, a wry turn of events, something utterly hilarious. And most importantly, something shareable.

What these stories demonstrate more than anything is the power of social sharing. Look at them and you’ll see they’ve earned a legion of ‘Likes’ and tweets. They have that unmistakable quality of a story that you instantly want to pass on to someone you know. If you could bottle it, or produce it on demand, wannabe “viral” marketers would bite your arm off for it.

Email: the real force in social sharing

And ultimately, I believe what unites these stories is that they are shareable in a very direct and personal way – by email.

Email is a vastly under-rated mechanism of sharing. I bet there are few news executives who can tell you whether their “send to a friend” facility sends more or less traffic to the site than the litter of Facebook and Twitter and Google+ icons splashed across the page. And you never see a “send to a friend” or “share by email” button with a share count next to it.

But it seems like email marketing had to be re-branded as part of “dark social” to make people notice it again, but there is a reason that ecommerce prefers email for selling things over Twitter or Facebook. And whether we like it or not, with content we are selling something – or at least hoping to buy some of the audience’s precious attention.

Publishers don’t do “content marketing” on old news. Nobody ever says “we had this great feature a couple of months ago, I’m sure we can wring a few more page views out of it if we re-promote it socially now”. But one of the things I noticed during Facebook and the Guardian’s ill-fated experiment with “frictionless sharing” was that individual articles could get literally millions of page views through aggressive social marketing. I think the gap between the number of people we reach with our content and the number of people we could reach if we produced less, but sold it harder, is immense.

Culturally this is problematic for an industry always rushing off to publish the new thing, but for me, a well-crafted feature interview about the 50th anniversary of the Rolling Stones is always going to be a good read, long after they’ve finally hung up their guitars, and shouldn’t be treated as “yesterday’s news”.

Should you make the fact that an old story is popular visible on your site? Over the years I’ve given careful thought to designing algorithms that reflect user activity. At BBC Online in the early 2000s, the homepage showed you “popular searches right now”. In truth, if we’d shown the absolute top three search terms, it would have invariably been “EastEnders” and “Weather” plus one other. What we actually did was take a snapshot every hour of the most popular search terms, then compare it to the snapshot four hours earlier, looking to see which terms had risen in popularity. That made the list topical.

With the Guardian Facebook app, we only allowed stories that had been published in the last couple of days to appear in the ‘most popular’ lists. Nobody is auditing your “most read” list, so find an algorithm that works for your business model.

And many businesses would kill to have this problem. Where we see an embarrassing old story clogging up our “most read” list, a more commercial operation would just see a newly effective landing page, and optimise it accordingly. If you’ve got a lot of traffic suddenly hitting a URL, why wouldn’t you remake that page, up-selling similar viral content, or your apps, or anything, rather than just letting an archive page languish untouched even as it becomes one of the biggest web assets you have?

Martin Belam is the founder of the Emblem consultancy.