Because there is an emerging set of standards and technologies that will allow you to view all your favorite news and information sources all in one convenient place. You can keep on top of a large number of sources easily and conveniently, and more easily tap into grassroots and alternative sources.
Everyday I read the top headlines from the New York Times, the Washington Post, Bloomberg News Service, CNN, the BBC, the Guardian, the Hindu (India), and the China Daily. I also monitor the AP and UPI newswires. I get the latest from the Onion and Salon's comics when they come online. I get the latest cycling news. And I read my friends' blogs. I never leave one page, I never waste time looking through my bookmarks, I never miss a story.
Start by looking at NewsIsFree, the best one-stop list of sources I've found. Its pretty extensive. I'll add more as I find good lists, and post a list of the sources I use.
You need a client, for the PC:
O'Reily Article about the differences in standards and some other technical information