With a community software like SBS I almost always think that video is better when it comes to teaching people best practices and how to utilize the tools SBS has to offer. The caveat here is to keep the tutorials short. Nothing more than 2 minutes long. Although visual video is better IMO than docs, threads, etc, it can backfire if it's 10 minutes long. You lose the interest of the viewer.
One thing that i always do is go through any documentation and look at particular chapters to determine if I could take that chapter out of the doc and create a video out of it. 9 times out of 10 you can, and still manage to keep the video short.
I should also add that I think it's extremely important to offer this type of best practices documentation whether it's in video, thread, doc form etc. I truly think that people struggle to initially see how powerful SBS really is when you dig in. It takes a while.