CNet reports what we all know - people who use DVR's skip the ads. This is hardly surprising, but I expect a response from the TV industry that's every bit as intelligent as the RIAA's response to downloadable music - denial followed by aggressive fighting against the inevitable. It's already started - newer ReplayTVs don't have commercial skip, and that feature has never been part of TiVo or the cable box DVRs on the market.
The problem is the business model. The industry is built on ad sponsored content, and time shifting just destroys that. As a commenter on CNet noted, no one is fooled into thinking that a fast forwarded ad counts as viewed. The logical answer would be to adapt - product placement, ad crawls (like the news crawls on the cable news networks), etc. That's not what I expect though. I expect a rear-guard action to somehow force viewers to watch ads. It'll be stupid, and it'll torque off viewers - but it's what I expect.