Please, have a look to the interesting presentation that +Todd Underwood showed in past November at Washington Usenix Meeting. Here you can find the audio, PDF and video version. Try the video, it worth to be seen.
Old good fella like me are always curious about how young guys are keeping on the golden SA's tradition, but, please, don't say to Todd that I called him "system administrator".
The scale of problem is dramatically changed in few years. Young SA can now store unbelievable computational power and quite infinite amount of data in the same area that was used in the past to guest a mainframe or to rack the VMS server disks. In the same time, the costs per cpu cycle and GB stored are cheaper. Hardware reliability and operating system robustness lowered the same.
The customers number changed also. Now, for big Internet companies, market is The Whole World, and they have to face everything is related to big numbers, not only in terms of capacity planning, network latency, bandwidth and reliability, but also by the cultural point of view and hourly coverage of the service exposed.
I'm pretty happy about one particular thing. One of the first requirements to be a good system administrator has always been to appear a bit weird to software people. I did my best in the past to accomplish the mission. Looking at Todd presentation, you will discover that it is still necessary :-)