When making my own books I usually keep the different novel/works of the same author in the same mobi file (since the Cybook lacks folder support). Since each novel will then be for instance 1/10 of the total length, the progress bar is useless (in addition to the progress bar not working on files with more than ~3k pages). I therefore often use the Internet to check how many pages the book I am currently reading on my Cybook has. This also goes for books I purchase where the mobi file consist of more than one novel (eg Paul Austerís New York Trilogy).
There might be different opinions on how a page number function should be made, but the current state of affairs is definitely an embarrassment for the software industry.
Possible better solutions includes any combination of:
- absolute page numbers embedded in the markup of each book, like suggested by Adobe
- percentages with decimals (only gives relative position)
- page number based on current rendering
- page numbers based on fixed amount of text/bytes on each page
(An on/off of feature, like with the current pagometer could be provided for the like of Ortep, who as I understand prefers to have sex in the dark ;-)