This wiki isn't set up with threaded discussion in mind. Discussions are flat, like those of a forum or board. Also, comments aren't numbered.
However, all posts including anonymous posts are signed automatically. You don't need to type one out in the comment box.
If you want to reply to a specific post, and the poster signed the post, the normal convention is to address the poster with "@Poster'sName:" on the first line of your reply. You could also begin with a link to the poster's User card, such as "[[ArielMT]]:" in a reply to a post by ArielMT.
If you want to reply to a specific anonymous post, the normal convention is to address the anonymous poster by the poster's timestamp. For example, if an anonymous user's post is signed as
- --Anonymous (Not signed in).....2014-12-02 20:24:13 -0800
then the convention is one of the following, depending on timing:
- ">>20:24" if you're replying within a day,
- ">>12-02" or ">>2014-12-02" if you're replying to the only anonymous post made on that day, or
- ">>2014-12-02 20:24" if you need to be very precise.
This mirrors as best as possible the normal conventions for completely anonymous forums such as 2ch, 4chan, and iichan.