Reddit was rewritten from Lisp to Python: <a href="http://www.aaronsw.com/weblog/rewritingreddit" rel="nofollow">http://www.aaronsw.com/weblog/rewritingreddit</a><p>Twitter from Ruby into Scala and JVM:
<a href="http://www.artima.com/scalazine/articles/twitter_on_scala.html" rel="nofollow">http://www.artima.com/scalazine/articles/twitter_on_scala.ht...</a><p>I think there are two aspects of a language (correct me if I am wrong) -- it's elegance/simplicity/breadth of code produced by programmers that write with it --- and then the efficiency/effectiveness/HW-optimized executable code produced by its compiler once it's run: so how does PHP and Facebook fit in with all this?