It seems one of the most asked questions I hear from people is about filters and what the secret sauce is.

Cloudmark’s processes which determine which IPs get a poor or suspect reputation in our CSI products, take into account many different factors, including both spam trap hits and volume of trusted end user complaints (hitting the “This is spam” button), reputation of the reverse DNS of the IP, reputation of the IP block that the IP is part of, and traffic volumes over time which help measure likely use of the IP in a snowshoe attack.
ISPs primarily want their email infrastructure to stay available and performing well, and for email recipients to receive the email that they want to receive. But if as a sender or marketer your email is going to spamtraps or people are hitting the “This is spam” button, then it’s not going to people who want it. Email blacklists and Cloudmark’s Sender Intelligence

Cloudmark is saying all the things deliverability experts tell senders. Maybe hearing it direct from the source will make the message stick better.

cloudmark • filtering • spam filtering