An interview I had asked my experience with large data sets and high traffic web sites and such and what I thought about them. I got an impression they were a bit shell shocked by the workload of a high traffic website. Many software paying positions and startup problems deal with large data sets vs. the small easy ones you usually deal with in client applications, many games, iPhone apps, etc.

It's because we need the techniques and tools to handle the ever-increasing amount of information in our lives.