The video breaks the 4 minute rule by a few seconds and is a bit longer then the past few.

Disclaimer: Use testing techniques sparingly as some of them could be considered spam.

Google will give you lots of seo advice. Simply feed google the questoin and they wil provide an answer.

For instance. Does google index duplicate content? Create some and google will let you know with real world results.

Which of your sites is the best to rank content? Create some similar content on multiple sites and google will tell you.

WHat is the best keyword density to use on my site? Create a few variations and get them indexed. Google will answer by the way the rank them.

You get the point. There is no need to debate many seo concepts, google is more than willing to give you the answers, just feed it some experiments.