"[...] 4.4 machine hours of automated tests to be exact. Over an hour of these tests are [...] Selenium. The rest of the time is [...] unit tests."

Impressive. But this not production test, where you tee the actual input from users into the system. Nor is it load test, where you measure whether or not the site is performant under real load. For that matter, there's nothing here that indicates you debug your operations (provision/deploy/backup) at all. My comment about not seeing such an operation stands.

Read a bit farther.

> Load average, cpu usage, php errors and dies and more are sampled by the push script, as a basis line. ... A minute later the push script again samples data across the cluster and if there has been a statistically significant regression then the revision is automatically rolled back.

Precisely so, but that's not testing, it's repair. You've just rolled back from a production problem automatically. The user still saw the problem.

Sorry if this seems rude. You're definitely way ahead of the game, but you're not addressing the thing that I'm talking about.

None taken. I don't work for IMVU.