Http://pokemondb.net/pokebase/meta/1218/i-think-i-know-who-anonymous-is
It explains that is a question was answered, and the answer has comments, then the answer is hidden, the comments are moved to the next comment-avalible location, because the question is hidden. It the comments were still there it would not make any sence.
For editors the question is still visible. for Non-editors, the commens say "edited by anonymous".
The anonymous isnt a person, its just an automatic site update, I guess...