> For example, a business might send promotional emails to its customers. By implementing SPF, DKIM, and DMARC, the business ensures that its emails are not marked as spam
But such emails can very well be (and in my experience usually are) spam. My spam filter will take the lack of implementation of these as a strong signal that the email may be spam, but does not think that just because these are implemented, the email isn't spam. As it should.
Just wanted to call this out because the article strongly implies that implementing these will let your email bypass spam filters.