Avid kaggle competitor, using R (extensively) and scikit-learn (somewhat):
At my day job I build predictive models for an insurance company
I joined SO in order to build enough rep to put a bounty on one question - which I did, and got an answer within a couple of days. Since then I've only asked two questions; whenever I start to ask a question the answer occurs to me as I'm typing it up (rubber duck debugging).