Learn English – What are the origins of “what’s up”

I don't know if google timeline gives any clues. Chicago Tribune used it in 1993, so it predates the web. A lot of the early references seem to be from golf!

Digging deeper, it's maybe an offshoot from 'You da man!' which goes back to 1990 and does seem to be a thing shouted on golf courses. That reference is from another Chicago newspaper.

Interesting question indeed!

It originally meant 'foolish, stupid':

1250–1300; Middle English: foolish, stupid

From Etymonline.com:

late 13c., "foolish, stupid, senseless

The following excerpt explains how the meaning of "nice" became changed so much:

"The sense development has been extraordinary, even for an adj." [Weekley] -- from "timid" (pre-1300); to "fussy, fastidious" (late 14c.); to "dainty, delicate" (c.1400); to "precise, careful" (1500s, preserved in such terms as a nice distinction and nice and early ); to "agreeable, delightful" (1769); to "kind, thoughtful" (1830). In 16c.-17c. it is often difficult to determine exactly what is meant when a writer uses this word.

Its meaning changed to become "agreeable" over a long period of time, and now, the reason for its connotation(wishy-washy sense) in modern times:

If any criticism is valid, it might be that the word is used too often and has become a cliché lacking the qualities of precision and intensity that are embodied in many of its synonyms.