For instant messaging, it’s easy to create a yahoo profile, or one for another IM service. Anyone who didn’t want to reveal their regular IM handle, etc, could create one specifically for using here.
If anyone is interested, my Yahoo id is kenradaniels.
IMing is a great way to discuss critiques. Chat would be great to have group discussions about how to find crit partners, and how to improve crit skills, etc, besides just talking.