Official Chat was a phpBB 3 forum registered at OfficialChat.net. It was created for the purpose of general discussions, and as an unofficial replacement to MCFT. Depending on the time of day, activity went from high to low, with much activity later on in the day in most western time zones. It was founded by Crenox, however it was owned and generally maintained by Phrossbite and Eve until May 2015, when the site was no longer functional.
Full article: History of the Original Chat Threads
Official Chat initially begun when Minecraft Forum Off Topic user Crenox found out about the, at the time, active Unofficial Chat PM. Motivated by the concept, he started discussing ideas with several users of the UCT, themselves becoming the first administrators of the forum to come. He set up a free ProphpBB forum at officialchat.prophpbb.com to serve as the chat. Two users, Zypharo and Phrossbite, purchased premium for the forum, which seemed to be a waste of money at first. However, it allowed Phross to make a backup and use it to migrate over to OfficialChat.net, which allowed the staff more freedom to customize the site to their preference.
Official Chat was originally a quiet, communal forum, with occasional new members joining for various reasons, such as the signature banners used on MCF and other forums, or members asking non-members who they are friends with, known colloquially as recruiting. A large new user influx came from Corvo's recruit-spree of users from MCFT, thus making OC more active than MCFT. Newer members continued to arrive through the aforementioned methods before the site shut down.
Members who have wiki pages can be found here: http://otterpedia.wikia.com/wiki/Category:Users
The full member list for Official Chat is no longer accessible.