It occurred to me the other day that I could generate a pretty big website just using some of the free content that's available over at
http://ezinearticles.com/. Let's say for example that I wanted to make a big website about weight loss. That's a fairly high dollar Adsense category, so there's an easy revenue stream, and Weight Watchers has an affiliate program, and so does eDiets. (eDiets is cool because they have a plan for every diet out there, including Atkins and the Zone.)
One site that generates revenue and is considered a great resource on the internet is
http://www.answers.com/. As near as I can tell, the content there comes from Wikipedia and some other sources, and none of the content is original or unique to Answers.com. It's just been "re-mixed" to use one of the common black hat phrases that describes what spam site builders do.
But here's the problem with that: duplicate content. Search engines don't like to rank pages with duplicate content very high, and it's entirely possible that you could build an entire site that's 100, 200, or even 500 pages long just using the articles from Ezine Articles only to have the whole thing nuked by the search engines for not having any original content.
The solution? Find ways to make the page that has each article on it less "like" other pages with that same article on it. Your web pages don't include just the text of your content; your web pages also include a sidebar or possibly two with menu items on it. That will help differentiate your content. You could also add a paragraph of your own introducing the article, and a paragraph of your own at the end of the article, with more of your own unique insights and comments.
In the footer of each page, you could add a list of hand-selected, on-topic links to authority sites related to the article's content, along with a description of each link.
You could also use different titles and descriptions for the page.
I've seen different tools that will measure in a percentage how "duplicate" content on one page is to another, and I've also seen different guidelines to how high or low that percentage can be without triggering a penalty. I've seen some guidelines that said no more than 10% duplicate content, and I've seen other guideleines that said no more than 40%. I've tried getting some pages built around the free content at Ezine Articles myself, and I was never able to get the number below 55% or so.
Honestly though...it took so much time and effort to get to that 55% point, I would have been better off writing my own original, unique articles. Or hiring a writer to write them for me.