I think having Materials Modeling as the name definitely dissuades people from joining (or, often, even looking at the site). These are potential users who would clearly fit into the scope we have established thus far, but who don't realize the site is for them.
The biggest examples I have seen of this are in advertising the site to computational chemists. Almost universally, their initial responseinitial response is that they don't consider themselves a materials researcher. They are generally confused as to how they fit under that umbrella and they would skip right over this site if they didn't have someone personally explaining to them that their work would fit here.
I feel Matter Modeling covers all the sorts of questions we are hoping the site will attract, without the name turning into an overly long list.