Just in case anyone was really wondering what this refers to (other than a rather uneven episode of the "X-Files"), please allow me to explain:

Our planet has been shaken by five major extinctions in
the four billion year history of life. The first, 450 million years ago, occurred shortly after the evolution of the first land-based plants and 100 million years after the Cambrian Explosion of animal life beneath the seas.

The second extinction spasm came 350 million years ago, causing the formation of coal forests. Then the Earth experienced two mass extinctions during the Triassic period, between 250 and 200 million years ago. The fifth mass extinction, probably caused by a giant meteor collision,
occurred 65 million years ago, at the end of the Cretaceous period, and ended the reptilian dominance of the Earth. This led to the current mammalian domination of the Earth.

So what is the Sixth Extinction? When is it coming? And
what is its cause? "It’s the next annihilation of vast numbers of species. It is happening now, and we, the human race, are its cause," explains Dr. Richard Leakey, the world’s most famous paleoanthropologist. Every year, between 17,000 and 100,000 species vanish from our planet, he says. "For the sake of argument, let’s assume the number is 50,000 a year. Whatever
way you look at it, we’re destroying the Earth at a rate comparable with the impact of a giant asteroid slamming into the planet, or even a shower of vast heavenly bodies."

Now then.  In my previous note about the decline (and, perhaps, fall) of newspapers, I referred to the Sixth Extinction – as part of a meme that I’ve explored elsewhere here comparing mass media companies to the massive and unwieldy dinosaurs that expired 65 million years ago, and the quicker, smarter webizens as the proto-mammals.  (There is always a danger that when you start talking about extinctions and asteriods and dinosaurs and such, that people will quickly and permanently assign you to that mental category of "Deranged guy who probably spends a lot of time sitting on benches in public spaces, explaining his theories of existence to his socks.")