Why is a Weblog Not a Bulletin Board?

I thought it ironic that the subject question popped up on another .edu weblog just a few short days after I was exchanging an opinion on the matter with an NCSU colleague.

I like their quoted answer better, but here was mine:

> That's an interesting question.  I haven't really stopped to think about it >     much until framing something to respond with.   >        >     Weblogs are an extension of the personal webpage, usually presented using >     some technology tool or system that makes it a little easier to keep >     updated - and the most common way of publishing and receiving updated data >     is time-based - which is why they end often being like a diary/journal - >     though I have seen essay sites that are like blogs, but the author(s) go >     back and edit previously published content, either to keep it updated or in >     a kind of "revisionist history" mode.  The Weblog is usually all about the >     author of the site and their personality/experience.  Or in cases where >     there is a shared or community blog, it becomes like a recurring >     newsletter/news site/magazine of sorts, governed again by the personalities >     of the publishers (which is why many in the so-called "blogosphere" are >     pushing the idea of blogs as new-media/new journalism).  In a way, there >     have been some powerful journalistic-esque things that have resulted. >     Individuals theoretically inside IRAQ blogging as the war started, Chinese >     bloggers writing clandestine accounts of life inside China, very Anne >     Frank, though now published immediately.  Voices are coming out of >     corporate entities, creating either a perception of accessible >     organizations (or ones having problems, which is getting some of the >     bloggers fired).   >        >     Blogs, like personal homepages, usually have a custom look and feel when >     you visit the site, and usually a unique voice of the individual writing >     the content for the site.   >        >     While many do have comments, and the comment threads on high-traffic blogs >     do become very similar to a bulletin board - a virtual, but fixed space >     where people congregate in discussion, there's usually not much of a >     conversation happening at the site of the blog.  Instead there's more of a >     reference model of individual sites linking to another site - very much >     like a continuously updated personal web page.  Collection sites (like >     http://www.technorati.com/ have sprung up, providing an aggregated view >     of the content, links, subjects of the weblogs, which tends to highlight >     pop subjects among the blogs informing those collection sites of updates. >     But those collection sites don't really have discussion on the pop subject, >     more they act as clearinghouses to find subjects that are being discussed >     by the individuals).   >        >     Writers of blogs tend to expound more than bulletin boards (e.g. TheWolfWeb >     [ed. a student-run bulletin board off campus], which I think is an >     example of the traditional bulletin board, where most of the threads >     consist of one-two sentences comments or provocations ;-) or responses >     to such) blog entries are usually longer.