your friendly neighborhood deliverability guide since 2001
When doing an IP warming schedule, should one factor in all of the domains for an ISP total subscriber count? For example, I should add up all the subscribers whose domains falls under the Hotmail ISP and use that total to determine my warming volume? Or should I just take each domain on it's own?
Susan, it's kind of hand-wavy, in that MOSTLY you would want to combine all Hotmail (Microsoft) domains if at all possible, and limit your volume to Hotmail based on volume to all of those domains en total. A handful of those domains aren't really Hotmail, but those ones would have such low volume that it wouldn't screw it up to include them. But totaling that all up isn't easy, so keep in mind that if a client is mostly focused on US, or starts warming based on US data, you only really have to worry about the US ones, and you don't have to query for all the other countries.
You should add apple/icloud to this list!
I've added Apple/iCloud info here: https://www.spamresource.com/2018/04/reference-apple-email-domains.html
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