youtube

Don't hesitate to contact me, if you need all your videos, comments, subtitles, annotations downloaded.

Check out this article: http://tubularinsights.com/backup-entire-youtube-channel-creators-tip-109/

Here is the direct backup link: https://takeout.google.com/settings/takeout#custom:youtube

You can also use the cool tool youtube-dl to have more control of your backup:

Downloading videos from Facebook: http://fbdown.net/down.php

I did not succeed with youtube-dl unfortunately.