On this blog, the date of a post is not necessarily the date the post was actually written. Blogger sorts posts by date, but lets blogger users edit the date. So, if I have an administrative post (or some other post that's generally not of interest to many people), I sometimes assign it a very old date, to keep it off the front page of the blog. Sometimes, I give posts a date in the future (for example, if I want to keep a post as the head post of the blog front page for a while).
Likewise, the first time I save a draft in blogger, it saves the current day as the day of the post. Blogger doesn't update that information, unless I manually update it. So, sometimes posts that I've been editing get posted with a date that doesn't reflect the actual publication date, but just the date that the post was originally edited. Also, sometimes, I may redate a post to bump it to the top of the blog.
This post falls into the first of those categories: an administrative post that probably no one cares about.
Lesson: Don't put too much stock in the date of the post.