Well this is an interesting detail: The court-ordered search Yahoo conducted, on the other hand, was done by a module attached to the Linux kernel - in other wo

Well this is an interesting detail: The court-ordered search Yahoo conducted, on the other hand, was done by a module attached to the Linux kernel - in other words, it was deeply buried near the core of the email server operating system, far below where mail sorting was handled In other words, a lot of effort was spent to hide the very existence of the code. Injected into systems in a stage far from the intended scope, and made to persist across upper level application rewrites. No wonder their security team freaked out when they discovered it.