It doesn't answer your question precisely, but I asked a similar (albeit more incredulous) question a few months back [1] and got a thread full of educated spec

It doesn't answer your question precisely, but I asked a similar (albeit more incredulous) question a few months back [1] and got a thread full of educated speculation from current and former Yahoo devs. [1] https://news.ycombinator.com/item?id=13180234 https://news.ycombinator.com/item?id=13180234