блог is “blog.” -издат (-izdat) is an abbreviation for the Russian word издательство (izdatle’ztvo), which means “publishing house.”
самиздат (“sam” for self and “-izdat”) is “self-published.” Samizdat was the technique of publishing forbidden texts in Soviet Russia. Dissidents found creative ways to publish information censored by authorities.
Today, self-publishing is simple. Install WordPress or the like, and off you go.
The challenge today is self-publishing something meaningful to share with others. That and, of course, having it read despite the vast amount of self-publishing available today.
With that in mind, Blogizdat seemed like a good name for a blog.