This is a configuration option in kune.properties, so ... I close this bug.
Feedback from Bastien:
Blogs in Kune are confusing. Before the public space and without supporting RSS, I wouldn't call them blogs. Having them adds confusion.
Besides, it's assumed as a common mistake to provide "too many features" at first to users, that is, dragging/showing features "because they are already implemented" (*).
Proposal: in new group creation, disable the "blogs" tool for now.
(*): E.g. Second point of http://javilop.com/startupea-inteligentemente/7-errores-que-cometi-en-mi-startup/ (Spanish)