It depends on what they are powering. In series, the voltage adds up and the mAh (current) stays the same. So if each AAA is 1.5V and deliver say 300 mAh by putting them in series they would deliver 300 mAh at 4.5V.
Using three 10440s in parallel the voltage stays the same (4.2V) but say each cell delivers 300 mAh, by running them in parallel, they should deliver 900 mAh.
At least I think this is correct. Im sure someone will jump in here and correct me if im wrong
EDIT: I guess one of the pros of AAA primaries is that they're cheap and available everywhere.