Jim McClellan sees blogs as a newsgroup replacement:Survival guide 2003: Blogs as newsgroups – exactly.
Usenet had two flaws – 1. it was unintuitive for non-techies to setup a new group. 2. People are individualistic and would rather carry on a discussion by posting to their own site and linking to others. EGroups, now Yahoo Groups, solved 1., weblogs solve both 1 and 2. A distributed discussion with individuality intact.
Technical reasons aside, the web took off largely because web pages can now be designed with pretty pictures, otherwise we would all be using something that looked like Minitel.