I just checked the page to see if it had loaded yet, and it's swirling around in a circular motion. Like it's a piece of paper that's been impaled on a spike and someone's twirling it. I have never seen a webpage do THAT before in my life.
I don't think it matters. I have a different address and just put that in as that is my correct, current tax info. I don't think they will cross reference the two. After filling it out it says "Valid". I'm sure Mturk will fuck it up, but for now it seems ok.
It's linked to Mturk. You access it through the Mturk website. It's just like the Paypal one. Governments are going after taxes from the little people with lemonade stands and Mturk accounts. Mturk, Paypal, Uber and every other gig economy type platform is collecting this tax information in similar ways.