So "back in the day" when I was an undergrad at MIT I signed up for every mailing list I could get myself onto and then trained a Bayesian spam filter to recognize free food emails. I threw all free-food e-mails in a freshly-untrained spam box and sure enough, after a few hundred e-mails it kept putting free food e-mails in one folder which was extremely convenient. Spamicity (i.e. free-food-icity) for phrases like "bring spoon" and "thesis defense" were particularly high.