Haha, well it's a book about Internet marketing (we wanted to create a practical step-by-step guide that read like a programming tutorial), so we've tried hundreds of things over the years and know what works. We made a promise to use only the things in the book to sell it.
We ended up changing the marketing messaging to "the ultimate growth hacking guide" from "a step-by-step guide to user acquisition" because that performed 200% better in our A/B tests, and I'm still a little bitter about that, but the money soothes my bitterness. So that was important.
Our biggest winners tactics-wise were sharing the first couple chapters on Medium and cheating a little bit, doing the same on Reddit, with a link that said "if you want more like this pre-order the book," and we worked Twitter pretty well and did a few guest speaking engagements, but no silver bullets, just a lot of lead ones.
