The name Cult of the Full Hub dates all the way back to the late ’90s. Originally, it was the name of King Lemming and Cynycal’s LAN gaming group (also known as a hub). The initial goal of the group was to fill it up to the cap of 8 people. Eventually, that goal was accomplished quite routinely.
In the year 2012, the name CoFH was used once again when King Lemming teamed up with Cynycal as Team CoFH to start modding for Minecraft, mostly for King Lemming to learn how to program in Java. The two were originally working on Brewcraft: a farming mod that contained a brewing overhaul for potions, as well as a way to make alcoholic beverages.
As King Lemming was still figuring out how to create Tile Entities, he created a furnace that worked on Minecraft Joules instead of items as fuel. He then figured he might as well make more blocks like that. Eventually, this development led to the release of the first version of Thermal Expansion for Minecraft 1.2, leaving Brewcraft abandoned. Back then, the mod contained about 7 machines and a few other things like Rockwool and Hardened Glass. TE was a BuildCraft addon: it required BuildCraft itself or addons like Forestry in order to power the machines with Minecraft Joules, BuildCraft’s old power system. It wasn’t until the third iteration that the mod became fully independent.
Since then, more people joined the team, Thermal Expansion got rewritten a bunch of times, new mods were made, some were abandoned again, and Minecraft Joules got replaced with the new Redstone Flux. Team CoFH is still around today, with their various mods still alive and being worked on.