Yes, it’s another yahoogle best practices post.
Google divide their requirements for senders into those sending more than 5,000 messages a day, and those sending less.
Yahoo divide their requirements into “All Senders” and “Bulk Senders”, and explicitly don’t define that via a volume threshold: “A bulk sender is classified as an email sender sending a significant volume of mail. We will not specify a volume threshold.”.
So … do you need to count how many messages you send, to see if Google thinks you’re a bulk sender or not?
Google state a threshold just so they don’t have to argue about the definition of “bulk sender”, I’m sure. In practice they’ll be using the same definition as bulk sender as Yahoo – we know it when we see it.
But the real distinction isn’t volume – it’s whether you’re professional, grown-up sender or a hobbyist.
If you’re reading this blog, or you have the word “email” or “marketing” in your job title, or send email to customers on behalf of your employer you should really, really be doing your best to comply with all the requirements.
If you send mail through an ESP then they should be doing their best to comply with all requirements, for you and all their other customers.
You can’t arithmetic your way out of having to comply.
On the other hand, the “less than 5,000 messages a day” / “All Senders” / “Really Low Bar” requirements are a basic threshold that everyone sending email should be complying with. Valid reverse DNS, authentication, don’t send spam.
Uncle Alfred bcc-ing his Xmas letter to 50 friends and family, or Cousin Gerald who runs a day spa in Toronto and sends out a newsletter to 80 regular customers via a legacy service that’s not been touched in a decade, or Professor Jenkins who’s the operator of the BIOINFORMATICS-L listserv at the University of Cambridge should all comply with that low bar (and, according to the data that’s been gathered, almost certainly comply already). But they don’t need to panic about the “Bulk Senders” / “5,000 Messages” / “Slightly Higher Bar” requirements. (Though anyone providing IT services to them will hopefully be adding some of the features piecemeal over the next few years, as services get migrated and software gets upgraded.)