I notice once in a while in my RSS aggregator that I am getting feeds that are sometimes two months old. Why would the aggregator be lagging on such stale news?

Y’know, I’ve noticed that this happens too with some frequency on my RSS reader, NewsGator, and I decided to dig into it a bit to find out what’s going on.

It turns out that the algorithm that RSS readers or aggregators use to figure out what snippets of news you haven’t seen is pretty simplistic; it’s all based on whether the last modification date is more recent than the last time you read the news from that site. Ordinarily, that’d work perfectly because just as with a newspaper, once an RSS feed from a Web site or Weblog adds a new item, it never changes and you only see it once.

But what do you think would happen if the site administrator is monkeying with…

[tags]rss,newsgator,rss reader,rss aggregator[/tags]