The term for uploading a blog posting is “publish,” although I am not quite comfortable with this. We expect a published work to be cast in stone. That is, if you read a reference to a quote from a specific book, you can find that book in a library, that edition, that page, and you will find that quote, unchanged and in context, exactly as anyone else in the world would have read it. Not with my blog postings.
If I am reading a posting, even one of several years ago, and I notice a misspelling or an awkward phrase (and I often do), I will fix it and update the posting on the spot, and no one will ever be the wiser. I have known several librarians who would roll over in their graves if they knew I was doing this.
But, after all, it is only a blog. Even if I documented the change, who would read it, who would care?
At The New Yorker magazine, every article goes through four editors, each with a specific responsibility, but all with the general responsibility of catching errors. I only have me, so I don’t beat myself up on errors. I just fix them when I find them.