sometimes if I publish articles on my website from wikipedia, the page rank will be affected or site will be adversely affected in terms of seo? Thanks!
if you use duplicate content, your content will get low rank, if any at all. unique content is number 1 rule on seo.
If, or when rather, the duplicate filter finds out, it'll definitely consider wikipedia's article as the one that will stay, because it was online first, and because it's such a reputable website. So you have a very little chance with G, more with other search engines... Good luck!
I think he is using the wikipedia articles for content gain and to bring relevant stuffs from vast pool of articles, might be to better facilitate his visitor and not to compete with wikipedia. I also dont have answer to the question whether you will be penalized for doing that....why dont you give little time for writting own content or brief wikipedia articles so that it is better understandable and different enough for search robots.
ok, but I known sites that have news content over 90% from the other sites (using RSS), and this sites are fairly well seen and positioned by google
That's why SEO is so much fun. There are so many exceptions to every assumed rule... That's usually because it's hard to isolate a factor, and there are always so many others involved.
Dont copy articles, you will not get far this way. Focus on original content, that is the way you should go.