I am a little confused by all this. I see that I can not share my comment on this post (the twitter and facebook check boxes are grayed out) but above your post in the little menu with the favorites button and the next entry buttons etc, the "share this" button is still activated. I tested it and it was going to let me post your journal entry to my Facebook. (Does that make sense?) Is that just always going to be the case for public posts? Grr.