Physics and compsci are almost level. Interestingly (to me, anyway) astronomy/astrophysics is a bit further towards a 50/50 split. (via Gender Composition of Academic Disciplines: PhDs in 2009 at Sociological Images)
Paul Mison's random stuff that doesn't go elsewhere. Is it microblogging, or microactivity?
(Previously known as 'tumblr is my sock drawer', for reasons that are somewhat unclear.)