You might be interested in a piece I wrote last year on how the traditional securities settlement system works (i.e. so you can compare/contrast):

http://gendal.wordpress.com/2014/01/05/a-simple-explanation-of-how-shares-move-around-the-securities-settlement-system/

And I jotted down some thoughts on how one might improve on today's Bitcoin exchanges here:

http://gendal.wordpress.com/2014/03/02/bitcoin-exchanges-are-more-centralised-than-traditional-exchanges-we-can-do-so-much-better-than-this/

You'll see that not everybody agreed with the views in my second post but hopefully it's useful food for thought.

Richard
(@gendal)