I'm pretty sure they ARE "section" or "paragraph" numbers. At any rate, no matter what you call them--location, section, paragraph--the idea is the same. For the average user they make no sense. Books use page numbers. Books are designed by writers and publishers. Programmers do NOT design books, thankfully, or they would be unreadable. So using a location system designed by programmers makes no sense. They should use page numbers. Almost all the eBook reader software I've used for PDAs, smartphones, iPods, etc. has used page nmbers which are recalculated if you change font sizes or fonts. That makes sense to the average reader, not location indicators.