Well allow me to be the lone dissenting opinion. (Edit: what follows should be interpreted as a rant against this practice, not against you personally, or your

Well allow me to be the lone dissenting opinion. (Edit: what follows should be interpreted as a rant against this practice, not against you personally, or your business idea :) Harvesting user's emails from a 3rd-party site that you plan to compete against is unequivocally and unambiguously a shitty, low, underhanded practice. Not to put too fine a point on it. You didn't put in the footwork or the dollars necessary to get those customers yourself. You didn't get the customer's permission to contact them (and NO, just because a customer posts his email address in plainview does NOT mean he's implicitly given you his permission.) You didn't achieve a real and meaningful relationship with your customers or your competitors. You just harvested some emails that were left in plainview, no different than any other 2nd-rate spammer on the net. Ethics aside, any business that depends on the glomming of email addresses/discussions from 3rd-party competitors is...the best word I can find is "uninspired". If you don't have a problem with this business model, you don't have a problem with targeted spam.