I am surprised I did not stumble upon or check for this feauture till now.
A few weeks after launch, Nokia released an update for a few American 808 PureView variants adding YouTube as an sharing option in the Gallery, along with the already supported Facebook and Flickr services.
Now this update was never released globally, and so I was under the impression that my 808 PureView still didn’t support uploading videos to YouTube directly from the gallery.
Turns out, Nokia added YouTube to the list of services supported by the gallery in the Nokia Belle FP2 update.
So if you have already updated your 808 to Belle FP2, you can also share videos via YouTube directly from the gallery!