Very interesting heuristic! I can see why data mining could be so useful for e.g. Paypal: analyzing data on known-fraudulent and known-valid transactions, looki

Very interesting heuristic! I can see why data mining could be so useful for e.g. Paypal: analyzing data on known-fraudulent and known-valid transactions, looking for unexpected correlations... Although in this particular case I wonder if the most benefit comes from simply flagging people who buy the product without trying it... and that is a heuristic that almost any SAAS could trivially implement.