Website contains you-tube videos ,so when a user clicks on the link is it default that he will land on respective video or is it necessary to have a you-tube account for the user??
If you are embedding Youtube videos in your website, redirect the visitor to the page where he can playback the video. User does not need to have Youtube account to view your videos.
you do need to have a youtube account but i would suggest that let the visitor watch a video on your site do let the visitor go ....... this can reduce your bounce rate
You need to have an account to upload a video. And yes it will increase bounce rate if user clicks on the video and leaves.
For youtube optimization, make good title and description and post your video on youtube and you can tag your video.