For most of the past few years, "aerobic" has been a pejorative adjective for cardiovascular conditioning. Interval training, buoyed by studies showing an increase in initial oxygen volume of the respiratory system (VO2 max) and relatively better fat reduction, was the rage. Many people, online and elsewhere, mocked the "cardio bunnies" who put in long, aerobic conditioning sessions and pointed to the supposedly interval-like nature of sporting events.
But now, aerobic is making a comeback. Here are some recent discussions on the subject:
Roadwork 2.0 at 8weeksout. I linked to this before.
Another bit by Joel, a long video discussing energy systems. Also previously linked.
The Return of Aerobic Work on T-Nation
This stuff isn't new - Rocky ran in the movie because practically every boxer did steady-state cardio in the old days, back when fights ran up to 15 rounds.
You can see the trend here - aerobic training isn't bad, it's actually quite good, and here's why. That interval stuff? Important but not like this is. The pendulum is swinging back. In a year or two, maybe more, maybe less, we'll hear "What happened to intervals? Everyone's doing aerobic conditioning now, and forgot how good these are."
For my part, I hate to see any tool tossed out of the toolbox, or any tool recommended as the one-and-only tool you need to reach any and all goals. A good cardio base can't hurt, and it's a mistake to try to get one purely by interval training. This tool is coming back into vogue but it never should have left.