Which email marketing 'opt-in' policy should you employ?

Which email marketing 'opt-in' policy should you employ? "Opt-in what?" 😳 Well, if you're not sure what I'm talking about, let me explain. Whenever you create a web form or landing page to collect subscribers' contact details (e.g. first name + email address) then you need to instruct your email marketing platform on how to opt your subscriber into your email list. Example web opt-in form There are two basic choices, 'single opt-in' or 'double opt-in' (a little bit like pouring cream). Single...