As a writer publishing on Amazon
For me as a writer, this means only one thing. I won't allow renting of my ebooks on Amazon, since that is the publishing platform that I am using at the moment.
As for length of stories on the ebook platform. A study showed that shorter stories are better for digital devices then longer stories, since it appears that people don't like to stare for long period of time on a screen, since it tires them (or the eyes). This means for me that my books (120+ pages) have to come out in print (I will deal with that once I get at that time).
I can't find the link to that study, but I found this link about similar subject, it's interesting in my view.
Here are the two stories I have published so far. I know that DRM doesn't work so it's disabled on all of my ebooks.
http://www.amazon.co.uk/gp/product/B00ZO9I9LE?*Version*=1&*entries*=0 (UK link).
http://www.amazon.co.uk/gp/product/B00M9WD38I?*Version*=1&*entries*=0 (UK link)
If the links are not here they have been removed by a moderator. I price all my short stories around 3€.