Competing TV screens or complementary TV screens? The CW has been cheered by media buyers not only because it offers a similar number of commercials online as it does on its traditional network, but because its young-skewing viewers "watch" the commercials to completion. (Media buyers also love that the CW's online CPMs are more in line with traditional TV CPMs -- way less than other premium digital TV content.) Some research executives would tell you that existing Nielsen measuring technology or any ratings measurement -- doesn't report "viewing" but rather "tuning." With the coming of future digital inventory, this will become more glaring. A recent study by Digital Clarity said 80% of those 25 and under use a second screen to communicate with friends while watching TV. That would represent virtually all the young-skewing audience of a network like the CW or MTV. So while viewers may "watch" commercials to completion online, we know this: they are doing something else while those ad messages are running. Now extrapolate this to older-skewing networks. Why? If the proponents of TV Everywhere get their way, all shows online will have nearly the same number of commercials as those on traditional TV. And one big, big not-too-friendly consumer function: they won't be able to fast-forward through those commercials. That will mean that use of second screens will surely rise among older viewers. Those who have DVRs -- now 40% of U.S. TV homes -- have changed their entertainment behavior dramatically when it comes to traditionally delivered commercials. Many DVR viewers -- some would say virtually all - fast-forward through commercials. Does anyone really believe viewers will go back to running to the kitchen for a snack or muting the volume of commercials when dialing up "Modern Family" on the ABC Full Episode Player? What will they be doing? A variation on what they did in the past: changing channels - or, using a digital world term, changing content. Many TV networks will then only hope that viewers -- if not looking at commercials -- will at least turn to their second screens to promote/share program content with other viewers. But then again, maybe they'll do something totally unconnected with traditional TV content or messaging. Then you'll have issues.