He specifically recommends
niche magazine ads, which then and today will probably get you a print + ad on their site. So like, take an ad out in PCGamer, and get yourself an ad on their website as well, if you're making an indie game. Better yet, find a magazine + website that specifically is about indie gaming.
I can't think of a single magazine that doesn't have an accompanying website.
EDIT: Might as well include my thoughts on the book. For me, it was the second "success genre" or "self help" style book I had read, the first being How to Win Friends and Influence People. I was about 22 at the time, fresh out of college, living abroad in Taiwan, trying to figure myself out and find myself. Very impactful time, so for me it was a very impactful book. Not so much for anything specific, but because the specifics were there. Here was a guy laying out concrete plans, concrete schedules, to making money. It guided me to how it really was possible to make money on my own, to live the kind of life I wanted to, to work remote etc. It planted a seed that took a long fucking time to grow, but it did grow, and the result is by the time I was 25 I had managed to sneak my way out of my liberal arts degree'd relatively futureless life into software engineering. Now my goals and objectives are framed by that first read - I haven't looked at it since, though I should.
In short, it's a great book for those new to the whole concept of working for yourself, creating a life for yourself, stepping outside the "normal boundaries" of life (go to school, get job, poop kids, die). Those on this site reading this may not think it's such a big deal, to those of us here it's pretty normal to step outside the box, but there's a reason I'm here now and this book contributed in a big way to it.