Notification when no new content has been published for X weeks from feeds

[thenamelessthing]

I have been collecting RSS feeds for some time now and enjoy reading my daily news updates. However, I often find that the content of my news feeds is sometimes lacking. When I start to investigate why, I realize that most of the time certain sources are becoming less active in publishing content. Often, some blogs have not had any new posts for several months. It would be useful to have a mechanism that could inform us when sources have not published for X weeks. I could then check whether the site is simply dead and look for a new source on the same topic.