1. What is the difference between Shoutcast and Icecast?
The differences between Shoutcast and Icecast are negligible, Icecast is open source software, meaning no license is required to use it. Shoutcast is commercially licensed and requires a license under certain circumstances. They do the same things albeit slightly differently.
2. What is AutoDJ?
AutoDJ is software which provides the user the opportunity to upload audio to a Shoutcast or Icecast server. You can then create and manage playlists which will keep your radio online without the need for keeping a computer online and connected at all times.
If you have multiple DJs on your station AutoDJ facilitates the switch between DJs.
3. What is bitrate?
The bitrate is the stream quality. For music 128kbps is the standard bitrate. It's considered "CD quality" audio. Talk-only radio can get away with 64kbps. Bare in mind, the higher the bitrate the better the quality, however, your listeners will need more bandwidth to listen. This could be a turnoff for listeners with low mobile data.
4. Do I need a license for online radio?
It depends. You do not need to show us a license to use our servers. However, you must ensure that you have a license to play any copyrighted music you intend to broadcast.
Each country has different laws governing broadcasting/streaming online. You will have to check your country's regulations to ensure you remain compliant. It is your responsibility to ensure that you have the appropriate license before you begin broadcasting.