Still having a problem with community bubble. Confluence 3.0
Space permissions are OK. If I create the space as a community then only I can comment or reply (the community permissions are set to all users are able to comment, create pages etc.) If I create the space as a space the forum macro still runs, and anyone can comment reply etc., but naturally none of the community macros will run.
To try to verify what's going on I created a "space" and commenting behaved as expected. I converted the "space" to a "community" and lost all ability (other than me) to comment.