Mandrill had over $1,000,000/mo in -paying- customers. We got no more time to transition off them than the free users did.

Switching e-mail providers is not something you can do overnight if you send large volumes (large volume does not mean spam: I send purchase receipts, contact forms, notifications, password resets -- transactional mail not ads). Even if you have a team of coders that can drop everything to start integrating alternatives, you need time to warm up your new IP space at a new provider, or your mail ends up in spam folders.

MailChimp screwed a lot of customers, and customers' customers when they gave only 60 days notice.

> My understanding of that is that the term customer shouldn't apply to free tier heroku spammers.

But they fucked over more than the free tier. We (work) had 15 clients that all had accounts that we managed for them. We probably spent upwards of $1200/mo on emails through those accounts.

We only got ~50 days of notice that we had to change over to another provider before we would get cut off.

We weren't free tier spammers either and we paid them a good amount of money for Mandrill. They changed their TOS to make it not possible to send out bulk mailings without using their managed and much more expensive MailChimp service. We are not spammers, we are a non-profit that sends digest emails of our content to those who specifically subscribe and confirm. We also have our own mailing system so we do not need the features MailChimp provides, we just need well instrumented SMTP.

We then switched to Amazon SES but still have a bitter feeling about MailChimp and will move our services that are using the full MailChimp product. Some of the change was indeed to control spammers, but when you are forcing over enterprises sending 100's of thousands of emails without complaint, that starts crossing the line where you want to better monetize your product. Giving your customers 60 days to engineer a different solution after they invested in your product is not good business.

So you are defending them (at least in the first sentence)from your speculation based on what you heard around town, that customers were simply not sustainable fits... Wouldn't it make sense they not offer a service package that is unsustainable in the first place? The clients myself and many others put on Mandrill were certainly not free tier anything, and they still offer the service, just under he Mailchimp name. (point being it can't be too unsustainable if they still offer it)

Customers I know who were ultimately stuck by being heavily integrated in the Mandrill API still suffered issues and downtime with the flawed account migration process. Just about every paying (and non paying) Mandrill customer got screwed in one way or another.