According to jumpedtheshark.com its a defining moment when you know your favorite television program has reached its peak. The instant that you know from now on...its all downhill. Some call it the climax. We call it jumping the shark.
Remember Happy Days? Remember the Fonz jumping the shark on waterskies. You get the idea.
Check out
www.jumpedtheshark.com for its comments on LOST. According to the poll it jumped the shark when Ana Lucia appeared as a character. I would agree.