For the IT guys on this thread. This reminds of comparison between Mac and PC.
Shia clergy is organized like Apple Macintosh system. Very sleek, good looking and highly centralized.
Sunni clergy is like PC. Operating system is developed by some and it is full of bugs, hardware by others. No central authority, anyone can do fatwa or insert a new card in the system.
Result:
Just like Mac, 10% or so market is for the Shia clergy. Just like PC, more than 80% "market" is reserved for Sunni clergy.
For the rest of 5-10% think Palm and Unix.
:)