Covering news by its’ very nature, will tend to generate lots of keyword rich posts. Issues of duplicate content which search engines are now really clamping down on, hardly exist because every news item will tend to be different. The result is that news article sites end up with thousands and even tens of thousands of search engine indexed pages very quickly. This in itself has an enormous impact on traffic. Lets say your site has 1,000 pages and each page attracts an average of only 5 persons a day through a keyword phrase keyed in a major search engine. That will give you daily traffic of 5,000 people. That’s huge and will enable you to make money from virtually any affiliate program, not to mention selling your own products or starting an effective donations scheme. And most of all, this is the sort of traffic that will give you a huge Google AdSense income. Not only that, with AdSense ads on all 1,000 pages, the odds of getting as many ads as possible clicked on increases dramatically Pimpandhost.
Contrast this to a situation where a non-news site has about 100 pages. Firstly because the pages are so few the average hits through search engines will be much lower. Actually it is bound to be closer to zero. How much money do you think you can earn from AdSense with only 100 pages? Not very much I can assure you.
This is the reason why the pros make a big effort to build up the number of pages on their sites. It of course helps a great deal if the site covers news articles. However many bloggers either hire a (low cost content provider) or post articles by other writers from article directories. Most actually do both and quickly end up with thousands of pages. The resultant impact on their income and revenue is huge.