Just looking at the first lesson, it looks very good. I would recommend reading though the whole thing. The table of contents shows a very well laid out course. It is oriented toward film but 99% is applicable to digital.
Well, I am not an expert. But I will offer my evaluation after about 5 minutes of overview.
The site is laid out extremely well.
The photographs on display assure the reader that the author knows what they are talking about.
The text supports the above claim.
Nothing that I have been taught and trained to do as a photojournalist and sports photographer directly contradicts with information contained in this site. (Further evidence that the site is indubitable.)
I spent a little time on this site a few months back. It covers some basic need-to-know photographic concepts. I had it as a bookmark until my computer went "fizzzzzzzzzzzz z z z... . . ." Thanks for reminiding me of this great resource.