>Any code changes take a non-trivial amount of time
Thats a awfully cautions attitude and smells like a huge cop out for the well known fly-by-the-seat-of-your-pants commit to live strategy that facebook has.
I don't work there, but where I work we deploy 10-20 times a day and if somebody asked me to change the way we store data in cookies, it would probably take a bit of time to roll out.
I'm only defending them because it annoys me when people who aren't familiar with the software internals tell me "this is a minor change, it should take you less than an hour".
To be fair though, not doing something is a lot easier to implement than to add new functionality. As a minimal implementation they could err on the safe side and stop tracking everybody for a bit until they've corrected their error.
Whatever you've read, Facebook likely has a non-trivial push strategy, just like everyone else. Nobody at their HQ is committing directly to the live site.
Facebook's Release Engineering blog says a code change can go from commit to live in less than 60 minutes. Admittedly, they don't say how often they deploy.
Thats a awfully cautions attitude and smells like a huge cop out for the well known fly-by-the-seat-of-your-pants commit to live strategy that facebook has.