What do you call belief in something despite good evidence to the contrary, or even taking lack of evidence (either way) as proof of its truth? What do you call it when this can be passed on from person to person, backed up by astounding stories and good oratory?

Personally, I'd call it David Icke's career!

Seriously though, I think everyone should be allowed to find their own faith (or even lack thereof). As Pete is doing in fact.

I don't disagree with allowing people to find their own faith, the question for me, as an outsider and as Pete says, is why do they do it?

As for benefits to the host, there are plenty of long standing memes that aren't beneficial, or might have been a long time ago but their utility has changed. For example, not eating pork. It's quite sensible in a desert environment but not so much when you have fridges. So the utility of that meme has shifted from "sensible diet" to a "badge of difference".

And I think there is something about this with faith too in that it helps to define in-groups and out-groups. This ideas seem pretty central to social survival.

As to my original point, "gullibility meme" sounds good and exists nowhere else on Google. So flippancy had some bearing there too.

Here's an interesting article on the matter: Simulating the Emergence of New Religious Movements.

IMHO it's also the fear Meme.

Fearing your life is worthless
Fearing an end to pleasure
Fearing it doesn't get better than this
Fearing that shit happens for no reason
Fearing the bad won't suffer
etc

Straw man, Steve.