The Web diary has perhaps seen its day, but I don't see weblogs going anywhere. But in many ways to me it is the the web diary that is more interesting. I'm pretty irrepresible. Blog and diary can probably be seen as end points on a continuum.
Narrative is optional, usually implied or inferred.
Diaries' whole purpose is to provide a direct impression of the person maintaining it. Narrative is essential and explicit. The degree of explicit exposition of narrative seems a decent candidate for figuring out where on this continuum a give site fits. I think Jakob has built a whole career on it. As in most forms of writing the results show.