Justin.tv is a video portal based around user broadcasting. All you need is a webcam and a free account, and you can immediately broadcast live to the world.
Getting a Justin.tv account is really simple, just enter your email, a password and date of birth and you're ready to go. As long as your webcam is ready, starting a broadcast takes only seconds. Your broadcasts are recorded, and you can choose to share them live or later, via Facebook or a direct link.
The ease of Justin.tv is its biggest attraction, although the downside of this is that a lot of the content is just people chatting to their webcams which isn't the best TV you're likely to watch. Other notable channels feature birdtables, aquariums, and live feed of a truck driver travelling the US.
While there are good safety guidelines in Justin.tv's help section, the openness of it means it has to be used with caution. Your profile and broadcasts are public and viewable by anyone.
Justin.tv is one of the easiest ways to be broadcasting, but it doesn't have the most engaging video content on the web.