When you are picking and choosing the articles for your niche sites, be very careful with what you are choosing. Be very sure that you are able to successfully generate traffic and make money from these sites. If you have the idea of trying to use the free website content articles, you may find it a bit difficult for you to choose one that have the exact keywords that you have used in your article that you have written, therefore you may have to either make some amendment to the articles that you have chosen to make it more appropriate (which some free content may not be allowed) or you may based on your own keywords on the articles that you find (which can cause you with very competitive keywords that takes a much longer time and money to attain a high ranking for). If you have the intention to buy content from the site, be very sure that you let the writer know what are your main keywords and what are your specific, your preferred keyword density and position are. Do always keep in mind that, once you choose and pick the wrong article to publish on your site, it can leave you with little or no traffic to your site at all and the ranking of the search engine will also be very low if the articles do not fit properly and appropriately with either your position or with keywords that are easy to attain high ranking for.