This is actually not true.

Articles are NOT duplicate content and if someone suggests they are, ask them why Yahoo and Google would have a Creative Commons area where they suggest you publish other peoples work. Search Engines understand that articles (similar to news) is meant to be syndicated.

Taking the time to write articles and to comment on other people’s articles, can actually give your traffic a huge boost. The more you write, the higher you will rank and remember to use your all important keyword text within your links.