When I read "fundamentally hard", I think NP-hard. What is NP-hard about twitter? Am I missing something or is this a reference to a systems development issue?
If it were easy to get it right, and profitable to execute correctly, I have to imagine that a competitor would have done so by now. But given the time and resource constraints, it seems that the problem remains difficult to manage, and I've always enjoyed that sort of challenge.
Developing heuristics for increasing statistical power, robustness, or informativeness is a mostly cerebral pursuit. Operations is more bloody in-the-trenches mud wrestling. And sometimes I look out from the ivory tower and I miss it.