You force who receives your letter to pay before he can be able to see the download link.
I don't think this method will work, who is going to pay 5 bucks for that.
I think you got trapped and you want to redeem your lost money by spreading this link.
I am not judging your intentions or calling you a scammer, I wish you can explain more.
According to my best awareness, this method isn't a scam or I wasn't a victim of scammer. Few days ago, I bought it from someone and followings are some truths I was realized.
1. It doesn't earn Bitcoins faster as the topic claims. Today, I launch bounty campaign herein bitcointalk.org forum and just sold 3 copies from 45 visitors (6%, conversion )
https://bitcointalksearch.org/topic/m.26380363
Anyway, it works with Twitter traffic. So, moved to Twitter based ad network.
2. The download formula eBook is an average guide. It doesn't explain any "super formula". But, it explains that what you've to do. Except that "the download formula" guide acts it self as a viral free traffic generation tool.
Honestly, at the moment I've made 11 x than I spent for this....but, not as faster as it feels when it reads the letter.