I think the Blog and the Newsletter can spread the same information, for two differents purposes, differents audiences:
- The newsletter is a community tools, for people who are in the community.
- The blog, is for people who not invest time in community, or for profissionnal who don't waste time with community,
The blog has utility for people doing technology watch via RSS readers like IT decisionner, Sysadmin, IT informations sites ( Distrowatch, Zdnet.....).
I repeat, it can be the same information, one article with become an article bloc, a Discourse subjet and a newsletter mail.