Frink didn’t really end the thread, it still exists.
There aren’t hundreds of people posting in Off-Topic (except for the hit and runners in the MySpleen thread), if you want to encourage more discussion and contributions, I suggest you make some more posts of your own that relate to Joker designs, rather than comments like “Uh… is this thread dead?”.
Stop being so anal about “off topic” posts. Allow the discussion of various Joker related things, like movies that he appears in. The conversation will eventually come back to Joker designs.
I probably would have posted something about Mark Hamill’s incredible voice work as the Joker, but I didn’t bother because your focus on the visual design alone is too narrow, and you are far too picky about people following your thread rules.