I have a person who is able to comment on posts without being registered. Their comments go to moderation. When I accept them, they show up normally but their name is unclickable.

If I search the database, they do not exist.  My guest access to forums is set correctly.

In researching further, I found the posts were created by user "0".

I searched user "0" and found a bunch of posts created years back, over a period of years, in other software (simplepress). These posts by "0" show up as "Anonymous", who joined "1 second ago".

The (current) guest's posts all go to moderation, though there is nothing hinky about them. 

Screen shots follow. Please help!