I go cycling around Cambridge and sometimes record my routes on Strava.
I'm a member of Cambridge Canoe Club.
I play football for Astrophysics in the University Social Club league.

I post very occasional drivel on Facebook (although it's too full of ads and tedious these days).
There is even less (but more, if you see what I mean) nonsense on Twitter (primarily posts from beer festivals, rating the beers).
I have a Blogger blog about networks and computers, mainly for my own use as a scratchpad.
I sometimes update Wikipedia as user Mincebert.