Consider mentioning your website or a page on your website within your videos.
"Check out www.mywebsite.com/something-people-like.htm For More Awesome Content"
The idea is that if you have a page on your website that provides value to your viewers - and they know about it - they will naturally link to it when they embed your video. The trick is figuring out exactly what people will find valuable (more valuable than your YouTube Channel) and effectively communicating that to your viewers.
It might be a good idea to promote your forum within your videos. I'm sure many people have questions and it doesn't apear to be very clear where to go.
Another idea would be to promote a like to your courses within your videos.
Hope that helps,
Scott
