Ok if i will write one Press Release and distribute on some press release site Now my question is same news article submission in all site so it going duplicate content ? or i need to submit uniq press release on every press release website ?
I have had this question myself a while back and it seems Matt Cutts addressed it in the video link below. To summarise, yes the content will be duplicated across the sites, however any site that uses these Press Release articles, if they are worth their salt, will curate the content and think how they can make the most of it whilst remaining unique. It's worth mentioning that the content will not be on your site, hence you will not be penalised. They have talented writers that will take your article and curate their own. Also many sites simple take a paragraph of the original article and provide a link to it. Check out Matt Cutts video here - http://www.webpronews.com/matt-cutts-addresses-duplicate-content-issue-in-new-video-2012-06 hope that helps?
Yes definitely it will be consider as a duplicate content if you will spread it out on many web pages.
I won't think it will be treated as a duplicate content. The Press Release is an announcement or news and news will be same for all websites and can be published by many websites. Only thing you need to take into consideration is these links won't last for long. It's depending upon the popularity and number of submissions in that sites. if the site getting more upcoming news articles especially popular ones, your content will be simply removed from their site.