Justin.tv claims they are the world's largest live video streaming website. You can create live video and show anyone in the world what's happening right now using your home computer or a laptop and share your event, class, party or thoughts, live, to anyone in over 250 countries while they chat in real-time with you and with other viewers. Justin.tv makes it fun, easy and fast to gather and engage with a live audience.
Live video motivates people who tell their friends and makes your video viral. They can follow you on Twitter, buy a product, donate to a cause or get up out of their chairs and take action.