On Habre it is possible to publish open tops, visible to all (including unregistered users), and can be closed, available only to subscribers of the blog that published the topic. This option is chosen by the author of the post when writing. However, there are several so-called offtopic-blogs, which by themselves are considered closed, and any post they caught, will be closed, regardless of the wishes of the author. Habr recently updated, and personal blogs were eliminated. Instead they got one common blog "Personal blogs", which is considered offtopik and, as a consequence, closed.
1) I Recommend to subscribe on Habrahabr — Announcements
2) One lock means that the topic is closed (for whatever reason: whether the author wanted, or the topic is closed blog). Two locks mean drafts: posts that are visible solely to the author. More castles, it seems, no.
3) See who is signed on "Personal blogs". The default seems to be signed were made (at least, I was signed), but someone could then unsubscribe.
4) She now is, your karma is enough. You just have to choose the right blog theme.