What’s the difference between the two certification whitelists for Receivers?
Both are whitelists, but because they have different origins and different pedigree, senders on one list are not necessarily on the other. Query both for inbox placement as both are whitelists for only legitimate permission based senders. Regarding special rules, look at businesses on the Safe list as legitimate business enterprises that follow best practices and use well configured, authenticated servers. Use the Certified list as a way to provide special treatment for the senders that measure up to the very best standards, and provide these senders with the privilege of turning gif’s and images on.
