Originally Posted by rishisab
It doesn't improve your website's PR.
But yes, if you have placed a link of your website in its description then you can get massive free traffic on your websites (of course, if your video is popular)..
I would agree with this. PR is unaffected because the links which you can place in the description are nofollow.
Traffic is possible but the last part of this comment is very relevant - just posting a video doesn't guarantee anything, it has to be something that is of interest to a lot of people before there is any real chance of there being any traffic generated. Traffic is of course good in itself, but again it will not affect PR.