I have seen many websites that take feeds from CNN, Topix and other major news websites. They show a part of the article and the permalink points to original source. Will google see that small part of the article as a duplicate content an penalise it? How can one SEO such a website whose content is not original?
If all the content on the site is belonging originally to another site then Google will just realise this is a low quality site with no unique content, thus the trust from Google will go down and then lower SERP's
It's very difficult. The search engines want unique content not just a bunch of copies of someone elses content.
Well, write your own unique content based on the orignal source; as-in explain your views and beliefs on the said article. This is how many of these sites work and achieve the rankings they have.
You can do SEO on copied content sites but they will never be showed in search engines. So no use of using all the SEO mumbo jumbo..
Well then what do you think about blog networks? They take feeds from their members and put in their site. like recruiting.com(PR 7). Also digg.com, It also contains some part of the content of the original website. but still they are favored.