What makes it a vanity domain?

Just imagine how much printed material has circulated since the 90s with the mdn.com address. Why do you want to break the web?

For JS developers, there is already a short-hand URL, mdn.io.

It's quite neat in its functionality, allowing for searches via url params, like so: mdn.io/promise

thanks for that. didn't realize that mdn.io existed.

It's a vanity url because it's small and can be used by tons of different orgs. Not sure why we're suddenly so sad about losing some tiny corner of the web that is very unlikely to have a huge effect irl.

I used to bookmark things judiciously 7-8 years ago, that bookmarks list is completely useless today because >90% of the links are dead, that's okay though, it's the way things go. Happens with real-world objects too, books go out of print, buildings get knocked down, not everything needs to be saved.

But people use it. You seem to think that being a web technologist gives you eminent domain over the web.