To continue, here is some of the best stuff I read (online, in English) during 2009. The previous list is here.
Wolfram Alpha and hubristic user interfaces (not entirely fair but still insightful and entertaining).
Why is programming fun (from Fred Brooks’ mythical book).
Mark Tarver: Hackers and fighters (a bit simplistic, but nice)
Feynman on teaching (again, some pages from the highly recommended “Surely you are joking … ” book)
More grad school advice (these are from Manuel Blum)
Ben Tilly: Teaching linear algebra (an interesting approach)