MailChimp's Email Genome Project scans billions of email addresses for information that can improve our deliverability and train Omnivore to recognize abuse. Our technology tests both negative results (like bounces and unsubscribes) and signs of engagement (like opens and clicks), showing us the big picture of any given campaign.
We're even scanning the content of emails for bad URLs and questionable keywords. We use blacklists, stats we've gathered, and our own technology to predict whether or not particular email content is going to cause a problem.
We're constantly studying and recording user-behavior patterns. This allows us to run a large-scale scan for users who might be sending campaigns too quickly or obviously trying to stay below MailChimp limits.
Thanks to Omnivore, we sent 50,000 warnings and shut down 45,905 malicious accounts in 2011 alone. Omnivore also teaches us valuable information that we can share with our subscribers, like the fact that a single opt-in list will have twice the amount of bounces as a double opt-in list.
Since our technology prevents abuse on such a massive scale, you'll achieve better deliverability by default — because even problem-free senders benefit from a self-cleaning system.
Omnivore exists not only to prevent abuse within MailChimp's system and maintain our reputation, but also to improve the email ecosystem as a whole. Because MailChimp cares about the ecosystem.