I tried removing the Goodreads reviews from Kobo today to see if that would make the advertising more effective, and I can't. Well, technically I can remove the reviews themselves, but the average star rating and number of reviews remain--you just can't see what the reviews actually say. Considering that Goodreads reviews level a star lower than, say, Amazon reviews, that's pretty much the worst outcome. So, the reviews stay, at least until Amazon yanks them.