I'm not so sure about this guy's advice.
If you start with a broad topic, like personal development, that has many sub-topics, you are going to have trouble ranking IMO. This may have been fine 6 years ago, but there is a lot of competition today - especially from people doing niche sites and optimizing for long-tail keywords. It seems to me that you would need to build up a considerable amount of content before you start getting ranked for anything useful. You may grab some long-tails just by luck, but using completely white-hat methods will leave you with a very steep uphill battle for any cash-generating traffic.
That's the whole point of going for a specific niche. Sure niche marketing will exclude people, but that's the point - restricting your traffic to those interested people who will BUY.
Unless you have a huge budget or tons of time and knowledge of your chosen broad topic, organic ranking is going to take a very long time. You may have an authority site / be an authority face for your topic in 3 years, but I believe that time can be spent on more profitable activities.
Monetizing with Adsense (what it sounds like he's hinting at) on a site like this could generate some money, but it's a gamble as to how much. It all depends on the traffic you can generate. You could build this into a huge content-rich site with lots of traffic and then sell advertising on it, but that can be a full time job. If that's what you like, go for it. If you are looking for more income at a faster rate, I would not take his advice.
He says all posts should be plain text. That's fine, and he's right about the search engines using it to index your content. However, including video is powerful - both for sales and for search. His own video is on YouTube! Not to mention Google's video sitemap capability. Posting your video on YouTube with a link to your blog and embedding that video in the related post (and linking from your Facebook page, Twitter feed, etc.) is a huge draw for visitors (and repeat visitors).
This may just be the cynical side of me talking... I know he gives some good info but I don't like the overall plan he's trying to sell to the audience. I wonder when one of these guys makes a presentation like this if he isn't trying to give lousy advice on purpose to stop competition before it starts and collect a fat paycheck from more speaking gigs.