A while ago we crated a few hundred videos. Some were good and some crap. We stopped as there was no way to make money from them and they were hard work. Since Google has launched the in video ads we now make around $1 per month from each of the videos we have on Youtube - it shows as Adsense for content host on your adsense account. If you're that way inclined and can make educational videos etc of maybe your mum knitting or something then there's money to be made. You can also put your sitename on the video (bottom left) and then promote your site as well. I think that around £8 per year per video is pretty good if you can make them quickly.