The genre began in earnest with shows such as Nummer 28 and Changing Rooms in the 1990s, then exploded as a phenomenon around 1999–2000 with the success of the series Big Brother and Survivor.  In the following years, these shows and a number of others (usually also competition-based) became global franchises, spawning local versions in dozens of countries. Reality television as a whole has become a fixture of television programming.
In the United States, various channels have retooled themselves to focus on reality TV, most famously MTV, which began in the 1980s as a music video pioneer, before switching to a nearly all-reality format in the early 2000s. There are gray areas around what is classified as reality television. Documentaries, television news, sports television, talk shows and traditional game shows are usually not classified as reality television, even though they also feature non-actors in unscripted situations.
Other genres that predate the reality television boom have sometimes been retroactively grouped into reality TV, including hidden camera shows such as Candid Camera (1948), talent-search shows such as The Original Amateur Hour (1948), documentary series about ordinary people such as the Up Series (1964), high-concept game shows such as The Dating Game (1965), home improvement shows such as This Old House (1979) and court shows featuring real-life cases such as The People's Court (1981).
There has been controversy over the extent to which reality television truly reflects reality. In many cases the entire premise of the show is a contrived one, based around a competition or another unusual situation. However, various shows have additionally been accused of using fakery in order to create more compelling television, such as having premeditated storylines and in some cases feeding participants lines of dialogue, focusing only on participants' most outlandish behavior, and altering events through editing and re-shoots.