More than 80 series of Big Brother have been broadcast to more than two billion people in 25 markets, yet to date it has only been banned in one country: Bahrain. Following demonstrations by Arabs who felt that the Big Brother format was offensive to their cultural and religious values, the government pulled it off the air.
It was bad news for Arabic advertisers as they had been flocking to support it - they were suddenly left with a Big Brother-shaped hole to fill in their schedules.
Ever since the launch of the Endemol-owned format in the Netherlands five years ago, reality-TV shows have come to dominate the schedules of commercial TV channels. In Germany, the fifth series of Big Brother which started on 1 March, spans an entire year.
Yet, while interest in Big Brother is beginning to level off (in some markets, broadcasters have failed to find a sponsor for the show), Europe's networks have continued, with varying degrees of success, to introduce new shows alongside derivatives of old formats.
In Germany, for instance, Ich bin ein Star ... Holt Mich Hier Raus! (I'm a Celebrity ... Get Me Out of Here!), which aired on RTL, attracted record audiences.
Juergen Kievit, the forecast manager at OMD Germany's Dusseldorf office, says Ich bin ein Star ... has been the most popular reality show of the year so far, emulating the success of the first Big Brother in 2000 and Pop Idol in 2003.
But, now the novelty factor has subsided, advertisers are no longer as eager as those in Bahrain. Manfred Kluge, the managing director of OMD Dusseldorf, says that some clients have resisted advertising around reality programmes.
He says that, while the genre still has appeal for some advertisers, the quality of the environment is a major concern and reality TV must be cheap to advertise in if it is to survive. The unpredictable nature of reality TV means that, until a show starts airing, advertisers have no guarantee that it will be a hit. And seeing that Euro 2004 and the Olympics will be on TV this summer, reality TV is up against some stiff competition.
A glance at this summer's offerings on Europe's TV stations reveals old reality favourites rubbing shoulders with some new, experimental formats.
Nearly all of France's reality shows, for instance, are Gallic versions of existing programmes from other markets and, over the summer, French networks are running several shows.
July sees the second series of Greg Le Millionaire, a French version of the US show Joe Millionaire; Koh Lanta, an adaptation of the Survivor format; L'ile de la Tentation (Temptation Island) and Star Academy, like Fame Academy.
However, there are some new reality formats in the autumn schedule. These include Sex Bomb on M6 in which a jury of women have to choose from 16 men the best dancer and stripper, and Finals, where a famous actor has to live the situation of a character he or she has played in a film, series or play.
Also on M6, there is a new and as- yet-unnamed game show schedule for broadcast in July about seduction and Le Chantier, where four couples compete to furnish an empty apartment. The most tasteful flat is judged the winner.
The plethora of reality shows available in France is a far cry from the tepid response which met reality TV's first foray into the country: Loft Story, the French version of Big Brother, caused a public outcry when it first aired in 2000, as it was seen as intrusive.
It was a completely different story in the Netherlands which, in many ways, is the spiritual home of reality TV: Big Brother debuted there in 1999 and was promptly spun off all over the world. However, according to Quinten Heller at Carat Netherlands, the existing formats are now past their best.
He says: "The main impact has been achieved and now the schedules are full of derivative spin-off shows, focused on minor celebrities or real people in real situations."
There have been attempts in the Netherlands to progress the reality genre, but some have proved to be ill-founded. For example, last year a programme called Masterplan was broadcast, which saw the players being controlled by a game master sending them SMS instructions that they had to comply with, for example, telling them to quit their jobs. The show was not a hit with the viewing public and it was pulled after just three weeks on air.
According to Heller, the Dutch take the concept of celebrity seriously and so traditionally many shows have focused on that.
But the series that involve real people are more extreme than broadcasters in other European countries would dare to transmit. In the past, there have been shows following a woman who is giving birth, a taxi driver with a hidden camera asking passengers to tell him their life stories and a wedding show where three couples compete to get married on-screen.
However, given that the Dutch continue to have a huge appetite for reality programming, Heller says the autumn/winter schedule will see the introduction of new programming formats, which the networks have yet to release.
For now, TV networks and production companies live in hope that their new formats will have the lucrative pulling power of a Big Brother or a Pop Idol.