The cases of hacking accounts with the use of viruses disguised as trade bots, trading platform, and also subscription for mailout, from which you may catch a virus if you follow a link in it, became more frequent. (coinsalad.com)
These tools allow you to put a form on your website to capture email addresses, send mass mailouts easily and automate your communications via «autoresponders». (bookmachine.org)
Let's assume each mailing list will get 5 different rounds of mailouts. (biggerpockets.com)