"Over-mailing = complaints = negative reputation at ISPs. Diversify less critical messages using Social Media. Save the good stuff for email."
"Drop the noreply@. Gmail’s begun testing turning on images for senders who have received two replies from a user; other ISPs should follow."
"Let the customer drive. From the onset and through Preference Centers let them dictate how much and what sort of email they want to receive."
"Stop marketing, at least occasionally. Actual content is likely to score better as ISPs look at engagement and complaints when filtering."
"Test, test, test. Day of the week, time of day, and level of personalization and segmentation will all improve engagement and pay dividends."
"Authentication will continue to be a major factor. Senders who have not adopted DKIM as their auth method of choice should do so this year."
"Just like DKIM, domain-level reputation is on the rise. For portability’s sake, make the From: and Friendly From as consistent as possible."
"Even though engagement, DKIM, and domain-rep may be on the rise they’re not the only factors. IP-based reputation still matters — a lot."
"ESPs can do many things but your content and frequency aren’t among them. What/when/how you mail is largely dependent on your deliverability."