As part of the process of writing my books, I've been reviewing a lot of my archived blog posts. That's brought up the question of whether it's okay to edit blog posts, essentially changing history (as I was working on this post, Jeff Korhan published one about how to rewrite your life story with social media).
My answer? It depends.
If there are typos, spelling errors or broken links, I would absolutely encourage you to edit those immediately, whenever you spot them (or someone else spots them for you).
If there are things you wish you had said differently or better, you can make those changes as well, however in that case I would add a note where you've made the change, e.g., [Edited on May 16, 2010] or at the end of your post, e.g., [This post was edited on May 16, 2010].
With my own blog recently celebrating its three-year anniversary, I've also been thinking a lot about how a blog is really a public chronicle of our evolution as writers, marketers and entrepreneurs.
While some older content may make me cringe and wish I'd known then what I know now, I try to celebrate my learning and how far I've come.
Can you edit your blog posts and change history? Certainly. Should you? That depends on your relationship with your past self.