I have always wondered.
The question becomes a thread if it isn't really a question. There are some exceptions though.
For example the DB server thread: http://pokemondb.net/pokebase/meta/28174/pokemon-database-showdown-server-welcome-other-metagames?show=28174#q28174
It isn't a question and is there really for information. Therefore it is a thread. A thread can also be when the user is wanting multiple different answers such as the moveset threads found on the Pokebase. MovesetBot will create all the moveset threads though.