Gravatar.com is a product of Automattic Inc. (WordPress).
Even the coders of BuddyPress.org (also a WordPress product) had to build a feature in order to be able to switch OFF Gravatar.com, because webmasters did request from BuddyPress.org to have the ability to disable Gravatar.com
Many webmasters did not like that Gravatar.com service and preferred to switch it off.
Would be good to disable...dont do what I did....just spent half an hour waiting for the vB importer to find gravatars for 20k+ members Surprised they didn't block me for abusing the API! (Props for the great vB importer btw!)
Yes, I would like to know how to turn off this s**t awful feature that probably 1% of our users will utilise. I must admit I'm puzzled why the XF developers haven't included, or as I saw mentioned don't plan to implement, a system for us to upload a selection of default avatars.