What you need to know about the world's most popular game streaming service, Twitch

Twitch was an accident. The live video streaming service, which boasts over 55 million unique users each month, began life in 2007 as "Justin.tv": an all-hours video livestream of co-founder Justin Kan's life. That wasn't the whole point of the service, of course; later that year, "Justin.tv" opened up to the public, who could then "livestream" to various "channels." At its inception, Justin.tv was a form of internet television, offering live broadcasts across a variety of topics. One such topic -- gaming -- took a particularly large portion of Justin.tv's audience. So much so that, in 2011, the company spun out gaming into its own website: Twitch.tv. Three years later and Justin.tv is dead, the company is now known as "Twitch Interactive," and Amazon just bought it for $970 million. Not too shabby for an "accident".