Get a ton of IP space while it was cheap and available several decades ago (mailchimp has multiple /17s and is old enough to drink). Mailgun was a Rackspace pr

Get a ton of IP space while it was cheap and available several decades ago (mailchimp has multiple /17s and is old enough to drink). Mailgun was a Rackspace product and had access to basically infinite amounts of Rackspace IPs. Mailjet and Mailgun are both owned by a marketing company. Other than that it's just a message queue exercise.