[greencat]

I'm not sure there's much deliberate gaming going on - just that some authors want to maximise their readership (rather than necessarily receiving a monetary reward for it). Amazon pretty much has the largest ebook readership so naturally these authors want to be there. Some may want their book to be paid for on Amazon but free elsewhere (but the Amazon T&Cs forbid it), others would simply like their book to be free everywhere.

Obviously Amazon is in the business of selling stuff so getting the balance between free and non-free is critical to them. Too much free content and people don't need or want to pay for any other. Too little and Kindle owners (potential and actual) might go elsewhere.

As you indicate convenience is a big factor. Personally, I'd pay 10-99c just for the ease of having a book delivered to my Kindle. If it's free - I won't even bother looking at other outlets.

The spbooks (spam-books) are a different matter. I think I read somewhere that, by traffic, Amazon is the 4th largest search engine in the world. Now they are in the content business and being targeted by spammers I suspect that search engine is going to get a lot tweaking over the coming years. They seem to be getting better at identifying republished Gutenberg works and removing duplicates - My guess is that they'll start being able to do the same with PLR material soon.

But the one thing that seems to guarantee a good position in Amazon's search engine are sales - unless the spammers can manufacture those - it's hard to imagine it getting too overwhelmed.