Somebody please 'splain self-publishing trends, like on Amazon?

[MorningGlow]

I am boggling at this: On another board (not DU), a writer posted the link to her e-book on Amazon. She was offering it for free and was hoping to reach 50K downloads (she was close to her goal). So I thought "What the hell" and downloaded it. I noticed she had more than 100 reviews, and her overall rating was four out of five stars. Impressive, I thought. And then I started reading.

Abominable. Horrendous. Catastrophically AWFUL.

I am not kidding--this was one of the worst things I have ever attempted to read in my entire life.
So...:wtf: How does something this bad get close to 50K downloads AND get a four-out-of-five-stars rating?

I'm also curious about how the Amazon system works in general; for instance, how do people find a book out of the myriad e-thingies offered? I don't believe this author blogs or is well known any other way. Do people just happen across it, read the description, think it sounds good, and download it? Would that really nab 50K people? (I'm not being skeptical--I truly want to understand the logistics of e-book trending.)

Somebody please enlighten me. In the meantime, I'll be in a fetal position in the corner, trying to block out the memories of what I've just read (and trying to stop worrying that e-pubbing is going to lower the bar for us all). :banghead: