There are two Dull Men's Clubs on Facebook. This article covers both.

Both have around 1.8M members. The smaller one features Andrew McKean, the main topic of that article. The other one--with the registered trademark symbol in the name on FB--appears to be more of a commercial enterprise, run by the Grover Click character.

I learned that the article is wrong on a point. All contemporary Dull Men's Clubs are copycats. The original is from 1980 and no longer exists.