Public stream:

Anyone at YouTube can see public videos. They can also be shared with anyone using YouTube. They're posted on your channel when you upload them and show up in search results and related video lists.

 

Private stream:

Private videos and playlists can only be seen by you and whomever you choose. Your private videos won’t appear in the Videos tab of your channel homepage. They also won't show up in YouTube's search results. YouTube systems and human reviewers may review private videos for ad suitability, copyright, and other abuse prevention mechanisms.

To share a private video:

  1. Sign in to YouTube Studio.
  2. From the left menu, select Content.
  3. Click the video you’d like to edit.
  4. Click the Visibility box and select Share privately.
  5. Enter the emails you'd like to share your video with, then select SAVE.

Comments are not available on private videos. If you want to allow comments on a video that's not publicly available, change the privacy setting to unlisted.

 

Unlisted stream:

Unlisted videos and playlists can be seen and shared by anyone with the link. Your unlisted videos won’t appear in the Videos tab of your channel homepage. They won't show up in YouTube's search results unless someone adds your unlisted video to a public playlist.

You can share an unlisted video's URL. Those you share the video with don't need a Google Account to see the video. Anyone with the link can also reshare it.