A TV format is the concept or formula demonstrated in an already existing TV show from which another producer can use to create a similar show in a different territory. In other words, if I’m a TV producer in the USA and I take notice of a TV show that airs in Denmark that could potentially be a hit in America, I would purchase the rights to that particular format, and reproduce the show for American audiences. A great example of this is singing competition shows. POP IDOL exists in the states as AMERICAN IDOL, in Canada as CANADIAN IDOL etc. There’s also THE VOICE which exists in several different countries all produced in different languages and use different judges. The most popular in the game show arena is WHO WANTS TO BE A MILLIONAIRE which has be sold to 108 territories. In the scripted world, a great example is THE OFFICE, which first started as a British series created by Ricky Gervais, and then sold as a format to NBC by executive producer Greg Daniels.
TV producers LOVE TV formats because they already exist as a proven entity. They are able to convey the tone and overall concept of the show to buyers by having the watch the show in its original format. The characters have already been developed, the general story line has been worked out and the overall look of the show has been established. This is much easier to work with than having to verbally pitch an original concept.