Turns out the Facebook team release features fully expecting them to contain bugs, concentrating on having efficient ways to rollback the code to a last known 'good' version. This is according to an interview with Jonathan Heiliger, the company's Vice President of Technical Operations.
This may go some way towards explaining why the new Facebook version currently in use by a good portion of 100 million people (including tens of thousands campaigning against it) seems to change subtly every single day, and why it contains so many bugs.
Of course, the company can get away with this only because users do not pay directly for content, and because of the ludicrously high demand for access to social networking. Facebook could use a flashing, pink background for an entire week and I doubt it'd lose even a third of its user base.
Most other firm's developers have to work towards preventing bugs, rather than expecting them, otherwise paying customers might very well look to a competitor for a better solution.
Despite the observations in the interview, at least some of the Facebook dev team apparently still like to wait until they have something that works.
We want to be certain to push out a stable and well received environment.
Whether or not this will actually happen remains to be seen. It also remains to be seen whether the firm will ever just give users what they find easiest to use, rather than trying to stay ahead of a big wave that isn't even moving.