I have about half a dozen news sites of which I consume the RSS/Atom feeds. Most all of them suck. Hard. The chief point of suckage is the amount of duplicates that they present in a given refresh. Typically, the duplicates are just that — redundant; as they don’t reflect any update to the underlying posting. In some cases you get the same posting with slightly different titles.
Perhaps one the most egregious I have encountered is the feed from the Cincinnati Enquirer’s site. In a given one hour refresh, it is not uncommon to see the same article 4-5 times, sometimes with slightly different titles, sometimes with a summary, sometimes with just the title (annoying in general). All of them point at the exact same article — so why all of the duplication? Judging from the horrid layout and extreme usability issues of the site in general, I would say that the answer is general incompetence of the people running the site.