Emacs brought Lisp mainstream, and Emacs Lisp at its heyday was arguably more popular than Clojure is now. The problem is that Emacs was the dominant text editor c. 1990, when the software world was much smaller than it is now, and has since been eclipsed by IDEs, GUI editors, etc.
AutoCAD brought Lisp mainstream for mechanical engineers, architects, and so many other 'rocket scientists' that I believe Emacs pales in comparison.
I was programming AutoLisp (automatic correction of trace and drill patterns for PCBs) on the machine which wasn't even able to build a decent Emacs in reasonable amount of time (PC AT/286 12Mhz with 2MB memory :-)). I was able to build myself an Emacs only after I got upgraded to 386SX 16Mhz with the whopping 4MB of RAM.
There was a period when Lisp was pretty large in industry as well, especially at places like BBN and NASA. Depends on how you measure, of course; those kinds of places don't do things that have a lot of end users, but the projects are large measured in dollar terms.
That's right. But I think it's going through a little renaissance. Emacs 21-24 has happened in a remarkably short time. With the Internet, many programmers are looking for better paradigms and find Lisp & functional programming.
