Originally Posted by Mike.Bean
You are able to put a link in the video descriptions. You can't make it a shortlink but I have generated revenue off of my links on the description of my youtube video's.
You should also make the link in the very first part of the description so people see that first without having to click on the "more description" button.
Yes, if you are making a video, whether it is for SEO purposes or not, you need to make sure to include a link to your site. Depending on what the video is about, you might want to make a special landing page to direct them to. So, if your video is about a particular product or line, you might want them to click on the link and go to a special page with those products offered at a slight discount.