Great for free users - my concern is that it won't scale or that they're not as profitable as they'd like to be.
Email campaigns are so easy in MailChimp and I'd like to maintain the look of those mails in my transactional mails. Nonetheless, you guys provide a great service!
http://blog.mailchimp.com/mailchimp-launches-transactional-e...
It rolled out this very week.
If that's really true, I don't imagine they will have to worry for a while.