Given a news article webpage (from any major news source such as times or bloomberg), I want to  identify the main article content on that page and throw out the other misc elements such as ads, menus, sidebars, user comments. 
What's a generic way of doing this that will work on most major news sites?  
What are some good tools or libraries for data mining? (preferably python based)
It might be more useful to extract the RSS feeds (<link type="application/rss+xml" href="..."/>) on that page and parse the data in the feed to get the main content.
Web scraping - how to identify main content on a webpage