So what page am I on?
None of my eBooks have page numbers.
If I change the font size I can change the number of pages in the book from 500 to 2500, no problem....
^^
Looks like the "Kindle Location" numbers are substitutes for page numbers in the Kindle eBook versions
When the Kindle first came out, it had a "location" code. For a typical book these run from 0 up to some 2000-12000. As far as I can tell, these units are somewhat arbitrary / meaningless from book to book. That is, two books of similar print length will have markedly different total #s of locations (two 250 page books might have 2800 locations and 5000 locations). However, the location specifies a unique point in the Kindle book that is consistent across devices. Typically the page shows a range of locations at a time on any device, depending on font and screen size.
Later, Kindle (and most others have this too) added
page numbers. These are
not dependent on font as noted above. Like the link I posted, they reference the print book's pages. The caveat is that, depending on your screen and font size, a screen may show less or more than one page, but I believe you can select the text and see it's page/location codes. You have to have the appropriate version of the hardware/software that supports this.
If you're a real stickler, I guess citing locations is better on the off chance that the Kindle edition is somehow different from the print edition, but I think this is kind of ridiculous, since if you cite the page number, the print and Kindle readers can both find where you are, and if you cite the location number, anyone who picks up a print copy of the book will not be able to find your citation easily.