Curious: what language do you currently use on the site? And how painful is it for you to not have Go or Rust?
(Also, you're talking about having the /content/ in those languages, right? Or supporting those languages in our code editor?)
I use Swift and Objective-C, but I've consulted InterviewCake content for every other language except PHP at some point. The sample data structures and question answers are nice code samples when I need a quick reminder for how to do basic things in languages that I don't use on a regular basis.
Not having Go or Rust isn't a big deal, if I could choose one it'd be Go. I want to learn Go for myself, and asking for a friend for Rust.
I also never use the editor on the site, I write/run the code on my machine. I never liked using the editor the few times I tried it. I see in another comment you made in this thread that a new one is coming soon, so I'm excited to try it. Any chance I could beta test? :)