I should have linked to this article when I saw it a few months ago:
Workers inside MySpace tell me that this infrastructure, which they say has "hundreds of hacks to make it scale that no one wants to touch" is hamstringing their ability to really compete.I seem to recall another article claiming that MySpace had no dev-test-live system; developers pushed code directly onto the live system. I can't find a this article, so maybe I dreamed it. Either way, could you imagine the fear of pushing new features if you had to work like that? Could you retain a single good developer if they were expected to work that way? (Post a comment if you can confirm this is true.)
I remember back when I worked at Microsoft that folks in the evangelism department bragged that they got MySpace to switch to Microsoft technologies like ASP.NETI remember reading about that and thinking, "Well, at least it got them off ColdFusion."