Yep - it's been asked! You can always cruise the forums (techniques) for answers. There are pages & pages of posts on journals in there!
Instructions from Lana for the matboard journals are here:
Forums at Splitcoaststampers
Instructions from Marcia and Heather (great PDF files!) for the LITTLE accordian book (the one where the inside is 1/2 sheet of 8 1/2 x 11) are here:
Forums at Splitcoaststampers
Marcia's has pics of the little book I made for Beate, and Heather's is a diagram so you can actually SEE what the pieces look like.
To answer YOUR questions, though. . .the spine things for the journals are what lets the matboard (or whatever stiff stuff you use) fold back so you can see the insides. On Accordian cards, you fan fold the cardstock, and adhere it to the covers of the books. You could ALSO do envelopes stuck together, tags tied together. . .the possibilities are without limit.
HTH