Just to be clear, I don't work for Facebook, I have no active engagements with Facebook, my story here is my own and does not necessarily represent that of IBM. I'd spent a little time at Facebook some time ago, I've talked with a few of its principal developers, and I've studied its architecture. That being said:
Facebook has a looming architectural governance challenge.
When I last visited the company, they had only a hundred of so developers, the bulk of whom fit cozily in one large war room. Honestly, it was little indistinguishable from a Really Nice college computer lab: nice work desks, great workstations, places where you could fuel up with caffeine and sugar. Dinner was served right there, so you never needed to leave. Were I a twenty-something with only a dog and a futon to my name, it would be been geek heaven. The code base at the time was, by my estimate, small enough that it was grokable, and the major functional bits were not so large and were sufficiently loosely coupled such that development could proceed along nearly independent threads of progress.
I'll reserve my opinions of Facebook's development and architectural maturity for now. But, I read with interest this article
that reports that Facebook plans to double in size in the coming year.
Oh my, the changes they are a comin'.
Let's be clear, there are certain limited conditions under which the maxim "give me PHP and a place to stand, and I will move the world" holds true. Those conditions include having a) a modest code base b) with no legacy friction c) growth and acceptance and limited competition that masks inefficiencies, d) a hyper energetic, manically focused group of developers e) who all fit pretty much in the same room. Relax any of those constraints, and Developing Really Really Hard just doesn't cut it any more.
Consider: the moment you break a development organization across offices, you introduce communication and coordination challenges. Add the crossing of time zones, and unless you've got some governance in place, architectural rot will slowly creep in and the flaws in your development culture will be magnified. The subtly different development cultures that will evolve in each office will yield subtly different textures of code; it's kind of like the evolutionary drift on which Darwin reported. If your architecture is well-structure, well-syndicated, and well-governed, you can more easily split the work across groups; if your architecture is poorly-structured, held in the tribal memory of only a few, and ungoverned, then you can rely on heroics for a while, but that's unsustainable. Your heros will dig in, burn out, or cash out.
Just to be clear, I'm not picking on Facebook. What's happening here is a story that every group that's at the threshold of complexity must cross. If you are outsourcing to India or China or across the city, if you are growing your staff to the point where the important architectural decisions no longer will fit in One Guy's Head, if you no longer have the time to just rewrite everything, if your growing customer base grows increasingly intolerant of capricious changes, then, like it or not, you've got to inject more discipline.
Now, I'm not advocating extreme, high ceremony measures. As a start, there are some fundamentals that will go a long way: establish a well-instrumented and well-automated build and release system; use some collaboration tools that channel work but also allow for serendipitous connections; codify and syndicate the system's load bearing wells/architectural decisions; create a culture of patterns and refactoring.
Remind your developers that what they do, each of of them, is valued; remind your developers there is more to life than coding.
It will be interesting to watch how Facebook metabolizes this growth. Some organizations are successful in so doing; many are not. But I really do wish Facebook success. If they thought the past few years were interesting times, my message to them is that the really interesting times are only now beginning. And I hope they enjoy the journey.