Anyone have something better than a wild guess about whether Lisp is getting more or less popular? It was never a very popular language in the first place, having lost out to the spawn of Algol.
At least in terms of the open-source community it feels much more lively now than, say, the early 2000s. There are new books like Practical Common Lisp and Land of Lisp, SBCL has matured into a solid implementation, Clozure CL was open-sourced, and Quicklisp has really improved the convenience of using libraries. I don't know whether that translates to more popularity overall, though.
If you mean the overall Lisp family, I think it's more clearly on an upward swing, especially due to Clojure's popularity (and if you're willing to stretch, Julia smuggles a Lisp-like language under cover of Matlab-like syntax).
+1 for Practical Common Lisp, great book, not as dry and academic as other Lisp books. For comparison, ANSI Common Lisp uses ray tracing as an example, whereas Practical Common Lisp uses an mp3 database.
You can check https://www.openhub.net (ex Ohloh) that tracks open source projects. Go to the tools section and compare languages. Lisp has been in decline for a long time, based on number of contributors and projects updated. Scala is doing exceptionally well
The graph does not look very convincing. It talks about 'the number of developers', while the vertical axis is labelled in %. What is it now numbers or percent. If percent, then of what?
If you mean the overall Lisp family, I think it's more clearly on an upward swing, especially due to Clojure's popularity (and if you're willing to stretch, Julia smuggles a Lisp-like language under cover of Matlab-like syntax).