This paper looks at blogs as dialogic action games characterized by specific communicative purposes and corresponding language use, as described in the MGM. The assumption is that web-mediated communication is particularly apt to developing simultaneous conversations within and without the scientific community. Using a small-scale study of blog threads originated by well-known economists who write for the academia as well as for the media, this paper looks at how they establish dialogicity and intertextuality in the post and at how they develop interwoven polylogues in comments, thus engaging participants in parallel conversations, some of which are more clearly oriented to sharing views, while others aim at knowledge dissemination and others still at knowledge construction proper.