Some of you may have noticed that the Nothing Wavering RSS feeds had some problems yesterday. For those interested, here is a technical explanation of what happened and what has been fixed. (Those not interested can just skip the rest and know that the problems are fixed.)
Every post in an RSS feed includes a Globally Unique Identifier or GUID that can be used to uniquely identify that post from all others. GUIDs are important because posts titles, post URLs, and post dates often change as people update their posts to correct misspellings, correct ambiguous text, or add updates. Even while all of these other values change, the GUID stays the same, and so when a program like Nothing Wavering or Google Reader reads the feed, it knows to simply update the existing post wit the same GUID instead of creating an all new duplicate post. So if you change the title of your post, Nothing Wavering should simply update the old post instead of creating a duplicate with a different title.