(Archived) Why does a Nook require an SD card?

[menevets 2]

I'm asking this more from a technical point of view and as a potential Nook purchaser. It's not problem for me to insert an SD card, I have plenty of them, I just want to know the whys and hows.

Are notes stored on the SD card or the onboard storage? What other metadata are stored on the SD?

How do your notes count toward the 1 gig non B&N content limit? I have about 2 gigs of notes.

If I wanted to test a Nook at B&N and brought my own blank SD to try EN, that'll work, right?

Thanks in advance.