Originally Posted by Elfwreck
I've seen plenty of books at Smashwords that have a preview that only includes the front matter. The preview is a set percentage of the book; if the real content doesn't start within that percentage, you don't get real content in the preview.
Smashwords allow the author to set the percentage that is available as a preview (I think it defaults to 15 or 20%, but I'm not sure). Other stores seem to use a fixed percentage.