Great minds think alike. I was thinking of doing a Topic Tuesday on the subject as well. I will defer to you though, Comsie.
I've done a RetCon on my the Half-Elven Warlock story. After discussing it with a local friend (not the ones from my Topic Tuesday: Beware of Advice), I realized I had some big plot holes, and everything that was published got revamped and re-edited. For online, and serial posted stories, like what you and I post a lot, I see RetCons as par for the course. They help in the creative process. Most Role-Playing companies, and Comicbook companies, judiciously use RetConing in order to control the direction of new stories.
I see it as a Vital Tool, in our toolbox as serial posters.