GW have been very good at the building market for what they call the 'Games Workshop hobby' by using warhammer 'evangelists' and they actually advertise for people to do this for them in White Dwarf. But one big advantage they have is the visual appeal of the miniatures, which may be why the D&D and SW miniatures games may often be the best route for stores or clubs to use in demonstration games.
It does help to back my argument that D&D needs to expand organically - not with money wasted on expensive press adds.
actually it just talks about how it is spread by word of mouth. how expensive a hobby it can be. the type of players it attracts. where they play. and so forth.