But isn't that the same as the automatic redirect you have in Wordpress when you change the URL of the post anyway? I'm trying to understand if there's any advantage to having this number stub over how WP redirects the URL's, but I don't think there is one. You're still going to get redirected links either way.
http://www.fastcolabs.com/3009577/
leads to the original article, and I assume will continue to link to the article as they add content.
I wonder how the adding of new content rather than the reorganisation and re-editing of the article will work from the point of view of prose style?