At the root of this problem is the confusion between the blog tool and the blog content. A blog is no more a diary than an empty notebook is a diary. Blogs become a diary when people use them to publish diary entries in the same way that a notebook becomes a diary when you write a diary entry in it.Well said !
But an empty notebook can also be a sketch book, a novel, an exercise book, a dictionary, or an infinite variety of other things, depending entirely on content. Equally, a blog can also be a tool for disseminating important news, or a project log, or a team building tool, or a marketing tool, or whatever its user chooses to make it.
In fact, blogs are a lightweight content management system which are easy to use, have strong archiving, cross referencing and search facilities, and are cost effective and flexible. That is what they are. A diary is what some people make them. (...)