Live streaming is important and a subject of post for internet and social media both aspects. YouTube is the largest video sharing, you can made your videos and upload it to your account and share with the world but that is not live or live streaming.
But there are some of website that you can use to broadcast yourself in real meaning. You can introduce your self live with thousands of person in real-time.
There are some software that you can download and install for the same purpose but if you use these online services you do not need any software to install.
To start live streaming you need a computer, internet connection and a web cam
Livestream is one of the popular online live streaming site. You can create your streaming channel and create live events. You can watch other live streaming channels. You can browse thousand streaming channels. Free and premium both options are available.
Ustream is perhaps most popular live streaming site. You can create your branding and your custom URL channel.
These three sites I know but two more sites I find useful are: