Popular Mechanics has an article titled The end of TV as we know it - Why the DVR revolution will be televised. Mr. Derene points out that we love television, but hate commercials. The acceptance and more prevalant use of Digital Video Recorders (DVR's) is "changing the delicate balance of the broadcasting world and in the process, the
basic measurements and accounting that the industry relies on"
He goes on to explain the DVR in laymans terms and why skipping commercials are so welcome to TV watchers
"DVR has empowered them to take back their television-watching experience from
the advertisers"
The result in over 17% of households using DVR's (I think that number should probably be much higher by the way) is that
"the advertising industry has been pressuring Neilsen, the company that for
years has been rating audience share, to move from its established “program
rating” system to an “ad rating” system."
In the end, DVR's are shifting some of the power from the media companies and advertisers to the viewers. Viewers watch what they want, when they want. The Washington Post has another article "Gone in 30 Seconds" about how the traditional 30 second TV Spot May Be Headed Toward Extinction As More Advertisers Pitch Their Messages on the Web. The ad executives are worried and noticibly changing tactics due to the DVR-effect.
Mr. Derene of Popular Mechanics also says, TV is evolving into "a more internet-like medium." I think internet actually will change Television even more as it becomes a major supplier and deliverer of content. Look at Joost, Babelgum, Netflix watch-now and YouTube. 
These internet-TV mediums are in their infancy and now considered a medium for tech-geeks, but it won't be long before they become mainstream. All it will take is to get the "internet-TV" to the average viewers TV. Joost is already taking this step in full-force. Joost is talking to hardware vendors about embedding Joost into set-top boxes and televisions. Duncan Riley at Techcrunch says "this will change the market as we know it" and I totally agree. Joost currently doesn't have much in the way of content, but they have made important agreements with content providers. All that is left for them is to increase their viewership to numbers that will get those content providers attention. Once that happens, the mainstream networks will want in on the action.
These internet-TV mediums are in their infancy and now considered a medium for tech-geeks, but it won't be long before they become mainstream. All it will take is to get the "internet-TV" to the average viewers TV. Joost is already taking this step in full-force. Joost is talking to hardware vendors about embedding Joost into set-top boxes and televisions. Duncan Riley at Techcrunch says "this will change the market as we know it" and I totally agree. Joost currently doesn't have much in the way of content, but they have made important agreements with content providers. All that is left for them is to increase their viewership to numbers that will get those content providers attention. Once that happens, the mainstream networks will want in on the action.