Pine (or Alpine) ;)

I love nearly everything about Pine, but I wish that Dovecot's IMAP searching was faster.

It's in MariaDB 5.1 and later.

http://kb.askmonty.org/en/pool-of-threads

Also, Pluggable authentication is in MariaDB 5.2 and later but I don't think that it ships with any plugins.

We handle a lot less traffic than Shopify (~15-20 million reqs a day) but ActiveRecord isn't a bottleneck and I wouldn't expect to to be [...unless you are talking about something other than the performance of AR as a body of code?]

Instead of "Rails doesn't scale" we should say "Rails runs on Ruby which means that it will consume significantly more CPU and more memory* compared to something else"

In my case, 1 extra server (my estimate) was a small price to pay for developer happiness.

* unless you are running JRuby