Right, it is Celine Dion for all of you.
This is the biggest shark jump in history!!!!!!
I'm failing to see how this is a shark jump at all, let alone the "biggest in history".
This was a monstrous hit song in 1997/8. Dion recorded it for her album "Let's Talk about Love" and it also appeared, obviously, on the "Titanic" soundtrack (although James Cameron was originally very hesitant to have a commercial song at the end). The song was #1 around the world, winning Academy awards, Grammies and Golden Globes. It is Dion's biggest hit to date. The song saw some limited sales due to the changing market (where CD singles were becoming less dominant in the U.S.). That said, enough CD singles were released (all were sold) for the song to be certified as Gold in the U.S. In Germany, the song sold over 2 million copies! It sold over a million in both the U.K. and France. Because of its immense popularity, it is considered Dion's signature song.
To say that she "jumped the shark" performing her biggest and best known hit is ridiculous. One might as well say of U2 when they perform any of their 80's classics. The same is true when we hear an old song by the Stones, Eagles, Billy Joel, Green Day, Bon Jovi, Springsteen, Madonna, etc. But we don't accuse any of them of "jumping the shark" because we love those songs and it's the artist's choice to perform them. This is Dion's song and it's her choice to sing it when she chooses.
You may strongly dislike Dion and that's fine. But your usage of the term "jump the shark" here is highly erroneous. You may feel that Dion herself is past her prime and that using her in a concert is "jumping the shark", but you'd also be wrong there. Dion just ended a wildly successful string of performances in Vegas. Again, don't let your personal bias dictate when something or someone is "past their prime".
It's my belief that most people always cherish the old, while over-analyzing the new. That's highly evident on this board, where 80's and early 90's U2 is adored, at the expense of more recent work. Old "Simpsons" is adored, even though the new is often far more witty and intelligent (and as a result, funnier). The same is true for anything that has a shelf life of longer than 5 years. But as evidenced in "Happy Days", where the term originated, the show remained highly popular for years after that shark episode. Yes, it was a corny episode, as were many of "Happy Days" episodes. But that was the point - light-hearted fun TV that was slighly nostalgic.
I think the best use of "jumping the shark" was pointed out very early in this thread, when a person wrote that using that very term is indeed, "jumping the shark".