Roll call threads were designed as basically just for people to say they're there and to start conversation. So essentially it was a primitive /oat/ general.
First created on /oat / in 2011 by user Drake Erternal, it had a short lived popularity, with other users creating their own roll call threads. The threads were made for /oat/ and their users, often having "oat roll call" in their title because most of the users on /oat/ didn't lurk or post on /chat /. This trend shortly died due to the majority of the threads being moved by moderators to /chat/ anyway.