[Sohcahtoa82]

It's a joke. Sadly, the origin is unknown, but it's a joke that's well over 10 years old.

[ben_w]

I believe it originates in the original dot.com bubble.

[dllthomas]

I'm pretty sure I heard it in an econ class, which would have been around y2k. From the way it was presented I had the sense that it was already well known.