This may be obvious to some people but i believe this is a good way to get your site referenced alot on related sites. If you're not that technicaly sound just use a free program like windows movie maker to make a nice text video ad, write a short little pitch for the product like an intro and then add your site address or whatever at the end. You can post clickable links in your video description plus just opening a youtube account can help because you can put a link in your profile and it's good for keywords etc. You can do this in like 10 minutes and after that you can go to other great video sites like revver, jumpcut, myspace, ourmedia and lot's more. What does this do? Well everyone knows that not all videos turn out popular, so, load it up with keywords and a good description and even if you don't get alot of hits on it, it can still benefit you on YouTube and Google. Googe adsense offers video ads now and if it's in a good category there's a strong chance that alot of sites featuring/talking about the same kind of product will use Youtube ads or simply target related youtube clips on their site. Within a week of doing this you may find your clip and the description for it embedded on alot of sites you've never even heard of. I promote Forex products and I've had this happen alot, when i search for my site I see it referenced on alot of sites I've never visited or posted on and all it's doing is pulling the data from YouTube or other video sites, so thus you can advertise that way on lot's of other related sites without them even realizing it, because of the way youtube works. Not to mention that youtube shows related videos beside every video you play directly on their site so it can show up alot that way too. It's nothing huge but it is a neat little trick.
Yeah, this method has been used quite a bit by a lot of people. I've never personally used it, but I can see how it would be great in a lot of niche's.