On Monte Cook's message board, Bruce Cordell of Wizards says that, given the way the submissions are coming in, he won't be at all surprised if they "break 20,000."
Monte himself, when he went to mail his submission, spoke to the guy at the post office. The man wanted to know why Wizards had been receiving "bags" of mail for the past days.
Someone said that Anthony Valterra, also of Wizards, made some comment about them bringing the daily mail in "in boxes."
I don't know exactly how much competition I was expecting, but it wasn't this much. Yeesh.