"Blogging is about talking to friends. Blogs are interactive, unlike newspapers, which just yak at you like some tedious, arrogant uncle." wrote Mary Schmich in an interesting article about blogs and blogging published in Chicago Tribune.
In Mary's opinion "depression is simply a failure to fully express yourself" and blogs cover the right and need of free expression.
A blog is most often one voice publishing to many. In contrast, community discussion groups are many people publishing to many. As such, they can be easily derailed off topic unless skillfully moderated.
Blogs are wonderful innovations. They emphasize the powers of the Net, personality, and instant publishing. Some are diaries of personal accounts, others for news. Like clothing, some extroverts enjoy wearing raincoats over hot pants on hot summers days, while others slap on a good old khaki pair of shorts and the always plain t-shirt. They are a tool for managing content -- and content is NOT going to disappear. So unless a better tool comes along, blogging is going to be here a while.