Email marketers are under increasing pressure to maintain ROIs from email campaigns. Even the most legitimate, opt-in-only, pieces are often blocked by recipients. If customers cannot receive the message, there is no reason for outsourced email marketing services to exist.
While the following piece references South African law, one could easily substitute CAN-SPAM (or another nation/states’ laws – see Spam Laws), and follow the same advice.
It is nice to see a “marketing” article recommend legal, responsible measures to get along with the system.
You can get the whole shebang from The art of getting your e-mails into your customer’s inbox.