Clubs are an SBC feature that has existed in two iterations. They allow you to make groups for anything you want, which can range from television, video games, internet, movies, books, spin-offs & literatures, or something completely random. You can join other peoples' groups to discuss the topic. Group owners can also appoint moderators and owners to control the individual club.
As Social Groups (2011-2012)
The first iteration of Clubs was as Social Groups on vBulletin. They were introduced with V7 in August 2011.
After the SBC Shut Down Spring 2012, Social Groups were lost. But they later returned on Invision Power Board on September 16th, 2012, with new features and in a new format. With the launch of Tiki 10 on Jan 1st, 2014, Social Groups were disabled from the forum due to lack of interest.
As Clubs (2017-present)
Clubs are a revived form of social groups, released for Squid 12 on August 15th, 2017.