Posted here because it has implications for anyone doing large amounts of email. Even if you play by the rules, you can still hit some serious snags if your users don't understand what those rules are.
I am beginning to think there might be a business model for email in this, that helps the larger providers and senders.
If you leave out Spam, who accounts for 80% of emails -- it's probably the large newsletters (guessing here.). The larger email providers can charge these newsletters, and the newsletters are assured of guaranteed delivery.
That said, I am sure I am not the first one to come up with this, anyone doing this already?
% spam has probably increased by this, as it is only a barrier to entry to mass-mailers that aren't spammers. Examples are: Paypal, EBay, airlines (although a lot of airline email looks like SPAM to me). You have to verify your identity with state-issued documents for some (all?) of those programs. There are a lot of restrictions (contractual and technical) applied to the messages that are sent through such programs. They are too expensive and risky for spammers to make money using them; in fact, they are too expensive for almost anybody to bother signing up for them.
