Think back to a few years ago - before Lenny Kravitz ever dreamt of toying with a hair straightener, before reality television had totally replaced quality Australian drama, before our Prime Minister was being likened to a rodent.

Think back to when Secret Life of Us was still on telly and it was really good. Evan was chasing Alex around their apartment, Kelly had been seduced by pyramid selling and was valiantly trying to pin down life's trifecta and Will was looking unshaven and happy (right up until his girlfriend Sam got squished under a semi).

And then three seasons later it happened - Alex and Rex married - and we all realised something the SLOU scriptwriters didn't. We knew that SLOU was all over. So when the show was "rested" mid-season earlier this year ("rested" being TV-speak for "taken out the back and shot"), none of us were surprised. SLOU had already "jumped the shark".

Jumptheshark.com is a site dedicated to chronicling the precise moment our favourite television shows hit their peak and simultaneously sounded the inevitable death knell for the program. A bit like what happens when an actor wins a Gold Logie.

Melrose Place jumped the shark when Dr Kimberley Shaw (aka Zipperhead) blew up the apartment complex. Because, let's face it, where do you go once you've blown up the set? On A Country Practice it happened when Molly died. 21 Jump Street flat-lined when Johnny Depp left and Richard Greico joined the cast. And Mad About You came to a screeching halt thanks to two words: Mabel Buchman.

So what does a TV show hitting its peak and then going into immediate decline have to do with sharks? I'm glad you asked.

The phrase "jump the shark" was coined by an American college student to describe the moment Happy Days hit the point of no return. Once Fonzie had done the ultimate motorcycle jump numerous times in Arnold's car park, the show's producers decided the only way to up the ante was to make The Fonz jump a shark on water-skis.

And so the phrase "jump the shark" was born. Of course, on jumptheshark.com Happy Days aficionados debate whether the shark jump was the true moment the show tanked or whether it was when Fonzie became a nag and started preaching about the importance of having a library card.

According to the site, there's no set formula or circumstance that guarantees a show will "jump", but there are certainly some tell-tale signs. The most common red flag is when two main characters are finally allowed to get together. Once the sexual tension goes, so does viewer interest.

Think Tony and Angela on Who's The Boss, David and Maddie on Moonlighting, Sam and Diane on Cheers, Niles and Daphne on Frasier. Of course, scriptwriters try to get around this by allowing a popular couple to finally "get it on" only to immediately break them up - a strategy I like to call "The J-Lo Effect".

On the other hand, if an actor has decided to leave a series, you can safely unite them with their true love and then immediately kill them. Take McLeod's Daughters - within weeks of Claire getting amorous with Alex, she went cliff-diving in a ute.

Other shark bait categories can include: graduations (think 90210 and Degrassi); deaths (Henry Blake on M.A.S.H., Mr Hooper on Sesame Street); new cute family members (cousin Oliver on The Brady Bunch, step-son Sam on Different Strokes, Andrew Keaton on Family Ties); puberty (Doogie Howser starts to shave); different actors playing the same character (Becky on Roseanne, Darren on Bewitched); bad silver facial make-up (Mr Bad on E Street); when Satan joins the cast (Marlena/the Devil on Days of Our Lives) or just the appearance of actor ted McGinley.

McGinley is the patron saint of jumptheshark.com since the site's creators have surmised that the moment McGinley makes an appearance on any program (Happy Days, Love Boat, Married With Children to name a few) it goes into immediate code blue. In other words, he's the television equivalent of the Ebola virus.

To their credit, not all shows fall victim to the shark. The Young Ones, Sea Change, Frontline and Fawlty Towers all went out on top, managing to stay one step ahead of strapping on the water-skis.

That said, it's not just TV programs that can jump the shark. It's open to anyone and anything: singers, actors, food (bok choy has had its day, my friends), scooters, dashboard hula girls, your parents.

Personally, I peaked in April 1996. I was school captain, we won the Greg Norman Trophy and I shaved almost every second day. It's been downhill for me ever since.