I presume that's built in? I've been using TMP to get the same functionality, but it uses F12 which gets swallowed by firebug if you have that enabled.
Yeah I used to use F12 with Tab Mix Plus until it was swallowed by Firebug, and that's when I discovered Ctrl-Shift-T, which is arguably easier to hit than F12 as well.
The problem with an obvious things you don't know wiki is that everyone doesn't know something different that's obvious. Putting all those things in one easy to find place makes them hard to find. And if you didn't know what you were looking for in the first place...
A wiki with "middle click opens in new tabs" would be noise for me. Nice thought though.
I think this is default behavior (thought I vaguely remember configuring it) -- on a computer without a mouse you can simultaneous left and right to open a new tab.