The board software automatically addes a “Poll:” to the beginning of all polls. When you start your subject line off with “Poll:” it will come out as “Poll: Poll:”.
I’ve never actually noticed any Poll Poll threads so apparently the vast majority of Dopers are in fact aware of this.
Well, there are currently two on the first page of IMHO, so there are certainly some.
It’s one way to indicate that a poll is forthcoming, for that time between when you submit the OP and get the poll options done.