In Defense Of Shark-Jumping, Ctd

A reader writes:

Fred Fox mistakes Jumping the Shark for a point of decline in popularity. Actually, it is about the aesthetic integrity of a character or show. Fonzie's jumping of the shark was the moment when the character Fonzie became not just self-parody, but even worse - an unaware self-parody. The character had destroyed that which made it interesting, or if you like, cool.

The phrase has nothing to do with popularity; it is a marker of when a show goes outside of its boundaries and in doing so destroys some of its characters' integrity. If you like, it marks the end of the beginning rather than the beginning of the end for a show.