It was amusing to see Deborah Rogers suggest that Facebook may have "jumped the shark".
The phrase originated from an episode of the US television series Happy Days in which, allegedly, the scriptwriters were so desperate to reverse falling ratings that they had the Fonz leap over a shark while waterskiing, wearing swimming trunks and his trademark leather jacket.
Unfortunately, the ploy had the opposite effect, and "jumping the shark" came to refer to anything that has lost all credibility or passed its sell-by date.
However, "jumping the shark" has now itself, er, jumped the shark and been superseded by "nuking the fridge". This derives from the most recent Indiana Jones film, in which Harrison Ford survives a nuclear explosion by hiding in a 1950s refrigerator. The fridge is lead-lined, you see.
Mark Dixon, Deputy editor, Octane magazine.