... I think that a subject will get bumped in Launch HQ after a certain number of suggestions requesting it get processed.
As you know, you can suggest a subject that is not currently on the list by writing it in the Can't find your subject? box located at the bottom of the Launch HQ page
Any suggestion made here will be reviewed by the Socratic team.
Now, if enough suggestions come in for a certain subject, that subject will be bumped in the list. At this point, contributors are welcome to sign up as founders.
I can't say what enough suggestions means -
Two suggestions coming from two different contributors? Now that will get the ball rolling! :D
So, to sum this up, once you suggest a subject, all you can really do is sit back and wait for other suggestions for the same subject to come in.