Do you have better deliverability though? You said you use Campaign Monitor for newsletters and those are a different type of mail than transactional emails from an application (much more likely to be flagged as spam too!). Seems like two different things and would be hard to compare.

Campaign Monitor isn't what you'd use for your apps, you want something like SendGrid.

Sendgrid + their whitelabel stuff (SPF/DKIM) = better than 99% delivery for over 100k emails/day.

SG is probably the most pleasant email-related experience I've ever had.

We use SendGrid too at my company. It's really great and easy. Integrating with their SMTP server is really simple.

thanks to @getsat and @potyl for providing some insight to their experience with SendGrid. we appreciate the testimonials!

the discussion around managing email in-house vs. paying a 3rd party to do it for you, is of significant complexity, as is evidenced by the length of the original 37sig post and this comment thread.

i think it's important for each and every company to evaluate their own unique situation - the needs of their product, the resources at their disposal, the role email plays in their overall business model, their relative experience/expertise in email vs. other elements of the customer experience they are building, the maturity of the company/product, etc. it would be very unwise to make a decision on this type of matter, based solely (or predominately) on factors like "successful company X does it this way", or "successful company Y does it that way."

every company is different, and they often face this specific decision at different junctures in their life cycle.

the most useful lesson that can be gleaned from this conversation (which i've really enjoyed following), is this: as a business leader, entrepreneur, developer, etc, you have options! if you want to do it yourself, it's possible -- if 37signals can do it, so can you. but if you don't want to do it yourself, or aren't confident in your ability (for whatever reason), then there are several awesome companies out there to choose from, each of which has its own strengths and weaknesses, which puts you in the position to select the most ideal solution for your unique circumstances.

that's all :)