To say that enterprise-wide visibility is a challenge in the security realm is a bit of an understatement. It's an important topic whose ramifications are felt quite acutely during breach response or incident response. Given that, you might find it quite surprising that more often than not, when crunch time comes, enterprises find out the hard way that they don't have the visibility and data they thought they did. Why is this the case? Further, what can an enterprise do proactively to avoid this type of situation? I discuss this topic in my post on the FireEye blog today, entitled "Flying Blind": http://www.fireeye.com/blog/corporate/2014/10/flying-blind.html.