Is the "$\pi$ is wrong"-movement serious or a joke? Is the "$\pi$ is wrong"-movement serious or is it to be taken as a joke?
https://www.tauday.com/tau-manifesto
If serious, what are they hoping to achieve? Throw out every book with $\pi$ in it and make up new ones with $\tau$?
 A: These people have a point. But they must know that their quest is doomed to failure. It's like proposing that humanity switches from base-10 to base-12 counting, because it's more logical. Or changing the sign of the electron's charge to $+$. Or using proportional representation to choose our elected leaders. Or switching to metric worldwide. Or...the list is endless.
Think of them as hobbyists rather than crusaders.
A: $\pi$ is actually a little bit better than $\tau$ according to The Pi Manifesto.
If people can't change the sign of electron, they won't change the quantity for $\pi$ either.
A: I'm pretty sure that some people seriously believe expressing things in terms of $\tau$ is a more useful convention than in terms of $2 \pi$.
Changing the convention, one must get people to adopt the new convention. If it's useful enough, then over time it will become known enough that its adherents can use it without explanation. If it's that much better, it will eventually replace the old convention.
Either outcome would be a desirable goal for those who believe such a thing.
A: “No, really.” :-)
They would rather replace $2\pi$ with $\tau$ as the common used constant.
The french revolution was one of the last events that led to some straightening out, dropping odd anglic measure units  (at least on the continent :-), weird currency units and tried to establish a better calendar, but the Thermidor etc. somehow did not get popular.
No idea what happens if Trump gets some funny ideas in this area.
A: Historically $\pi$ made alot of sense, the ratio between circumference and diameter.
It just happens to be that diameter is unhandy, and radius is so much more often used.
That's why $\tau$ could be used.
It is not about burning books, it is more about publishing books with $\tau$ in the future.
From my experience there is no real need for it tho.
A: I get the impression it's not the most serious debate, but Numberphile has done several videos on the subject. https://m.youtube.com/watch?v=ZPv1UV0rD8U
