(Common) Lisp usually gets more use than exposure, so it's nice to see large-scale Lisp success stories. Makes me feel warm and fuzzy inside, as it's one of my two favourite languages (the other one being, of course, C).
Edit: APL is a close third, but let's be realistic.
APL is the ITS of the programming world: Both are immensely powerful and quirky, and were designed by people with a real allergy to typing. It would be nice if there were an Open Source APL which was the equivalent of SBCL in terms of being the default and feature-complete implementation; it would also be nice if APL were elegant as opposed to merely terse.
"On Lisp" is a good book but perhaps too advanced for an introduction, whereas his "ANSI Common Lisp"[0] is better suited to the purpose. Barski's "Land of Lisp" has also received positive feedback.[1]
I'd be interested to see what others consider a suitable general learning path for Lisp.
The usual starting book is 'Practical Common Lisp' by Peter Seibel. Some advanced stuff then in 'Common Lisp Recipes' by Edi Weitz. Some older advanced stuff with examples: Paradigms of Artificial Intelligence Programming, Cases Studies in Common Lisp (PAIP) by Peter Norvig.
What made you think it was “no longer in use?” It’s a very big world. Just because something isn’t mentioned regularly in headlines doesn’t mean it’s not out there.
I would imagine Clojure has more use than Lisp. It's a valid question which is better to learn, not one I'm qualified to answer, though. All I would say is that the Clojure community seems more active, and less prickly than the Lisp one.
This is getting downvoted and I don't see why. CL is easily in the top 10 programming languages I see mentioned on HN and it also comes up regularly outside of HN, yet the amount of people actually using it in production seems miniscule.