I was so proud of my review that I decided I might as well post it to Amazon--why not?
The page that allows one to preview the review correctly displays text markup stuff like italics. So thinking it was just as I wanted it, I published it. However, when the review showed up on the site, all the markups were annoyingly displayed throughout the text naked--wads of various characters and punctuation marks.
Once I tried to edit a review and the edits never showed up, so I thought instead of editing this one I'd just delete it and rewrite it with no text fanciness. However, when I tried to save that one, OOPS! I'm not allowed to write more than one review for a product.
And while it's easy to look up any product, it's hard as heck to navigate and find information on Amazon's own processes. I often just go to Google and look up whatever Amazon operation I want and get in from there, because Amazon sure as heck isn't going to help me navigate itself.