Back of the envelop estimate of cost savings for the decreasing number of calls to SF311
The decreasing call volume is reported as primarily due to a reduction in SFMTA transit calls as a result of better on line access to MTA data[A]

 	Avg daily calls	Annual Calls	YOY % Change	YOY Annual Calls	$/call	Savings
Apr-11	8,586		3,133,890 	-
Apr-12	6,720	 	2,452,800 	-21.7%	 	(681,090)		1.96[B]	 $(1,334,936)

Sources:
[A]http://sfcontroller.org/Modules/ShowDocument.aspx?documentid=3234
[B]http://bit.ly/MLm8Uh