To Publish: to issue for distribution to the public; to make publicly known.
To Self-Publish: the publishing of books and other media by the author of those works, rather than by established third-party publishers.
How you view self-publishing probably depends on where you are in your writing career. You could see it as investing more money than you are likely to see in return. Maybe even as pure laziness; the author didn't want to invest the time to find a publisher, what does that say about the authors work? What about blogs?
Blogging: a type of website, usually maintained by an individual with regular entries. Many provide commentary or news on a particular subject.
By definition, a blog is (usually) a free way to self-publish views on particular subjects and provide samples of work to the public. It is a collection of thoughts and ideas put in a friendly format to share.
Still not sure your blog is a work of self-publication? Go to an editors guidelines, look for what they will accept. Do they accept previously published works? Some do, others don't. Look closer at the ones that do NOT accept work that's been available to the public, 'includes any posting of this work on blogs or other web sites.' Guess what? You've been self-publishing in your blog!
Wait a minute. You didn't make any money putting your story/article/review on your blog and now you may not. All your hard work out there for free. Did you realize that when you started typing away and updating your blog?
Blogging is a great tool for those who write for the joy of writing, without getting paid. It's also a great self-promotional tool. Publishing in a blog means you are giving your readers a taste of your style and flare, which could work to your advantage as a writer.
What will you self-publish today?