YouTube reports here
that they will let users mark videos as "unlisted." These unlisted videos can only be seen by using the video's direct link. An unlised video won't show up in search results or be visible on the uploader's YouTube channel.
With this feature, you can mark your videos as "unlisted." This means only people who have the link to the video will be able to watch it. It won’t appear in any of YouTube's public pages, in search results, on your personal channel or on the browse page. It's a private video, except you don't need a YouTube account to watch it and there is no limit to the number of people who can view it. You'll get a link when you upload the video and then it's up to you to decide who to share it with. Unlisted is the perfect option for that class project, video from last summer's family reunion or your secret Broadway audition tape.
An example for a good use of the unlisted feature, given on the YouTube post, is a teacher who wants to share a video project with parents and classmates, but does not want the entire world to be able to find the video. People do not have to logged in to YouTube to be able to view these unlisted videos.