I strongly agree with this comment. Sure, all us nerds know the Fail Whale. And Twitter is sort-of mainstream, but has nowhere near the adoption of Facebook — and those mainstream users, even when seeing the fail whale, may not know it goes by that name.
Now while I enjoy the artwork here, and it’s clever, this error page strikes me as
1. Overly nerd-centric / in-joke (Edit: I am referring to the Twitter reference, not the use of the word “fail” here)
2. Unprofessional (the word “fail” used as a noun)
3. Derivative.