Paper on purely functional data structures (persistence): <a href="https://www.cs.cmu.edu/~rwh/theses/okasaki.pdf" rel="nofollow">https://www.cs.cmu.edu/~rwh/theses/okasaki.pdf</a><p>Clojure's fantastic contribution to mainstream programming is making these types widely available.
High number of "Rich needs to get his act together" comments this year. There's always a few in the comments, but its a much higher percentage this time around. More than a few who said they left after Rich's "clarification" of how he views open source last year.