One of my bigger annoyances about RSS feeds is that many large media outlets feel it necessary to add query strings to the URLs in their RSS feeds. Among the offenders are the New York Times, the Washington Post, and Slate.
Why is this annoying? I use Sage, a Mozilla Firefox extension, as my RSS reader. RSS feeds are stored in one of the folders in my bookmarks, allowing easy addition and deletion. Unless desktop RSS readers, the majority of which use the Internet Explorer ActiveX control, I get the security benefits of the Gecko rendering engine. Most importantly, I get integration with my browser cache. If I read an article elsewhere, but see it in my RSS feed later, I will realize that I have already read it (as I have modified Sage to make read links turn pink).
But without unique URLs, Firefox will not recognize that I have already seen the article. This is especially problematic with articles from "NYTimes" and "WaPo," as they are used all over the blogosphere. I contacted the Post about the issue, but the man who responded was unsure whether anyone else who used the RSS feed had cared enough to complain. Sigh.