Here is a list of registered users who think they have committed to the Mathematica proposal but who are not showing up in the list of committers that I can see.
(Sal and Pillsy previously committed as unregistered and have obviously been trying to rectify this.)
It is not obvious enough to new Area 51 users that their commitment only counts if they have confirmed their email address. Strangely, the commitment screen asks for your real name but not your email address, and it does not say anything about needing to confirm your email address before your commitment counts.
(I just selected a random proposal I wasn't already committed to, to show this)
Please add some suitable BIG BOLD text to the commitment screen along the lines of "You must confirm your email address for the commitment to take effect. Please check your spam-catcher if you do not receive the email shortly.".
Right now many "commitments" are meaningless, unbeknowst to the user.