This posting will self-destruct in 36 hours.

Well, it won’t actually vanish. But most of its audience will be gone by then — because, according to a new study, the lifespan of a news item on a website follows a power-law curve: The readership for a story is biggest in the first day and a half, decays rapidly, then flattens out into a long tail. That’s what Albert-László Barabási, the famous network-theory scientist, discovered when he observed the browsing behavior of 250,000 visitors to a Hungarian news site. As PhysicsWeb reports:

Barabasi’s team calculated the “half-life” of a news document, which corresponds to the period in which half of all visitors that eventually access it have visited. The researchers found that the overall half-life distribution follows a power law, which indicates that most news items have a very short lifetime, although a few continue to be accessed well beyond this period. The average half-life of a news item is just 36 hours, or one and a half days after it is released.

I can definitely attest that this is true, by looking at my own blog’s log files. Whenever I get tied up in work and can’t blog — as in the last two weeks — my readership drops quickly until it reaches a long-tail equilibrium, and stays there. Then when I start posting again it zips back upwards. So long as I post regularly, there’s always a large audience, because the rolling 36-hour periods for each posting overlap.

That funky graphic above has something to do with the study — I’m not 100% just what, but it looked pretty cool so I included it.

(Thanks to Morgan for this one!)