A friend has a video on Youtube they have made private, added my email in so that it sends me a link to view it.

1)  What setting /is there a setting to stop me from forwarding it on to someone else to watch?  or I can forward it on but it will not play for them?

2)  I do not appear to be able to play it unless they have first set the video to 'Unlisted'.  Any ideas why?

3) Some emails entered are changed before they are sent.  (e.g.  name@xxx.org.uk  changes to namexxx@gmail.com)  Any idea why this is happening?

:-\

Hi Judi,

There are 3 settings for YouTube videos - private, unlisted and public.
Unlisted videos cannot be found but can be viewed by anyone who has the link. So links can be forwarded on to friends.
Private videos can only be viewed by invitation.
The help screen says, "You can invite others to view your private video by entering in their email addresses below. Invitees must sign in to their Google Account to view your private video."
The bold bit might explain why email address are getting changed to gmail addresses as private videos can only be watched by people signed into their own Google accounts.
Unlisted videos are easier to share and forward, and you don't need to be logged into your Google account to view them.
Keith