Richard Faragher added that many of the mooted possibilities for why centenarians live longer could actually be examples of reverse causation. For example, the idea that having a positive mental outlook can help you live for a very long time might, at least in part, be rooted in people being more sanguine because they have better health.

“When was the last time you had a really positive mental attitude and toothache?” he said.

Richard Faragher said [...] just because centenarians had certain habits, it did not mean those habits were driving their longevity – an error in logic known as “survivorship bias”. [...] Faragher said both theories, however, resulted in the same warning: “Never, ever take health and lifestyle tips from a centenarian.”

Web pages are ghosts: they’re like images projected onto a wall. They aren’t durable. If you turn off the projector (i.e. web server), the picture disappears. If you know how to run a projector, and you can keep it running all the time, you can have a web site.