Hi,
I would like to know if it is possible to embed a youtube/vimeo/… video in a Blender view to follow tutorials for exemple.
You can use the “Download YouTube” Firefox plugin to download the video (make sure you have rights) and then in the node editor use it as an image texture source for a plane or other shape. It will generate one frame per frame of the movie and you can add in sound afterward.
I found a simpler way ^^
Use VLC to stream the video and place it on a view of Blender.
For this, you need an addon for VLC > http://addons.videolan.org/content/show.php/+Youtube+video+and+playlist+importer?content=149909
And you can view video and playlists directly !
I use deskpin to put VLC on top.
It will be great to have an addon to do this or a blender feature.
OH! I thought you meant to create your own tutorial videos as an output from Blender. LOL! 
Yours is a good idea. I never thought of it before.
What I’ve always done is to simply hit alt-tab to switch back and forth between a browser window and Blender.
Difficult to switch sometimes so have an incorporated player will be really usefull.