So I don't broaden the term "blog" to cover all manner of web sites with dated articles, because that'd make "blog" a relatively useless term. I stick by (near as I can tell) the original meaning where I think the single-author aspect was an important part of the definition. I'm quite sure the rest of the world won't keep "blog" narrowly defined (and thus useful), however. :)
You're perfectly right. Though most modern blogs although very differing each other in their visual appearance, also have something in common that makes them recognizable at a glance. For example, even Gmane now offers a blog-like web inferface, which some people may be more comfortable with.