A short posting on the Gmail blog announcing that Gmail now supports 25,000 contacts caught my attention. 25,000 contacts? Ok, now suppose you do have that many. Gmail gives you 128 KB of storage space per contact. If my arithmetic serves me right, that adds up to a total of 3 GB of disk space. Multiply that by however many customers Gmail has, and it adds up to a hell of a lot of additional disks they potentially have to provide.