e-mail blast to xx million Craigslist (or PayPal or e-Bay etc, etc) double opted in users
I've always deleted them before
But do they get any response?
(If you got a 0.01% response e-mailing 37,000,000 that's still 3,700 new people coming to your site??!!)
Are they really double opt-in or are you going to get accused of spamming?
Anyone ever used these and what experience did you have please?