Can I use one encoding cloud for multiple sites?

Yes you can use an encoding cloud for as many sites/webapps as you like. Each encoding cloud is a separate data store of videos, encodings and profiles.

If you give an webapp access to an encoding cloud, it will be able to view all of the videos in the cloud. However, because videos use unique IDs, if you like you can control which of your webapp's users can actually see the videos on the server side.

If you are setting setting up video services for several separate unrelated parties, using a different encoding cloud for each ensures that their data is kept safe and separated.

Each encoding cloud also has own control over how many workers are active. If some of your webapps have a large volume of videos being uploaded, you can increase the number of workers doing the encoding work for just those webapps. By having more workers, and encoding cloud can encode more videos simultaneously, and your users will have to wait a shorter amount of time before their uploads have completed encoding.