Hey there everyone! Avatars and signatures are now (once again) allowed in the forums. Avatars have been disabled for awhile and signatures for about a day and a half. Please keep them small though - animations are discouraged. Thanks!
Signatures always have and always will only appear in posts where you checked the "Attach signature" option. If you don't want to manually have to check this option each time, be sure to go into your Profile and check off to always attach your sig. :)