Difficult is totally subjective. It's probably the most resource intensive just because of how many different pages there are, but to me that's not what makes

Difficult is totally subjective. It's probably the most resource intensive just because of how many different pages there are, but to me that's not what makes a problem difficult. Also, I could see this ranking high for consumer-level problems, but there are way more difficult (both resource intensive AND hard to figure out) and interesting problems when you look at some of the business applications.