He's actually got two posts about it, that I've found to be insightful and useful to take back to my own reading:

    http://blog.fogus.me/2012/02/22/reading/
    http://blog.fogus.me/2012/05/23/extreme-reading/

I've always been a horribly slow reader, despite enjoying reading and reading at a high level. A lot of that slowness is actually about the time I devote to reading (toilet time and bed time, essentially), the level of interest I have in the material (usually "enough to continue"), and a symptom of my out-of-practice reading skill, which leads to me primarily subvocalizing instead of reading, and frequently backtracking. Spending 10-15 minutes every other day reading at 200 words per minute does not make for a quick journey through a book.

After thinking of it in those terms, I've started to apply the idea that the more I read, the faster I will read (up to a point), to actively avoid subvocalization, and to devote real blocks of time to reading instead of fitting it in at the edges. I find that I end up reading closer to 400 wpm during focused time, and when I want to, I'm able to average 1-2 hours/day of a week. Spending that much time at 400ish words per minute makes books fly past. Keeping comprehension up and realizing value is where taking some notes comes into it.

Beyond that, as he says, you have to know what you're reading a book for. For example, it's probably not worth reading the introduction and basic content chapters of technical books you're already up-to-speed on, and you can skip right to the important parts and just read them deeply.