Earlier quoted context omitted.
> make the link point to a page that says "Sorry, we're still working on [feature X]. Check back soon!" and avoid looking like an amateur? You've officially missed the point of the article. The argument is not that you look like an amateur, but that the user thinks the problem is with their computer or ISP. Since most 404's are due to user error in URI entry, web filters or cross-site link rot, this is a reasonable a…
Maybe I've just got more tech-savvy friends than most, but I don't know anyone who assumes a 404 when following an internal link is their fault. Usually they just assume that the webmaster was sloppy. Why not use a 503 Service Unavailable? This is telling (stretching ;-)) the truth, and people do assume that a 503 is temporary, because that's the explicit point of the message. And you can throw in an e-mail link, lik…
A 404.. I find, not so much.