That's a reference to KTIV still broadcasting on VHF 4 a looped program about the DTV transition, how to get your tv signals, use of a converter box, etc. The FCC set up some rules just prior to Feb 17 after the deadline got pushed into June and a lot of markets said "we're still switching on Feb 17". From what I remember reading, at least 1 station in a market had to run this broadcast for a period of time after Feb 17. That is, every station in the market couldn't just go dark on the analog signal. Apparently, PBS stations didn't count, because Iowa Public Television kept all their analog signals on and are still running the dual signal (analog and digital).
As I recall, it's a cost issue and expensive for a commercial station to run both analog and digital transmitters at the same time, so many wanted to switch as soon as they could.