Even with extensive search of material, I think many of the "niche" fetishes took a long time to popularize. And often it is one or couple mans passion, where they do things with very little of financial success.
Think of magazines such as Splosh for example. Everybody talked about, it was sold in all porn shops... but often ending up to discount bins, since very very few really cared for it.
Perhaps it's theme of its own, but you could simply look at supply of material compare it with publishers and their location.
Denmark - everything, including bondage, spanking, rubber, animals, etc
Sweden - a lot, yet I don't remember than many swedish bondage mags? Most often regular sleaze
UK - spanking, caning, school uniforms, rubber, sissy/crossdressing, etc. nowadays seems like most transgenred magazines come from Uk.
Germany - fistfuck, hc s/m, housewives, shit, piss, rubber fetish combined with them, adult babies.. etc
US - soft bondage, big boobs, high heels etc..
JAP - focus on girl often in most exaggerated objectification. All specialities one can imagine has been used for ages. Good example for example those Timeless magazine stuff published with fetishistic drawings of schoolgirl being mangled to pieces while hit by train. From book in mid 50's..
Of course this is hardly a good study, but often you can see specific type of stuff coming from specific country or publisher. Does it tell something about nation and its history (or laws), or simply about fact that publishers followed their own tastes? I doubt most people do large market research - but they do what they want and it creates the market.
PORN GOLD book is worth getting. 1988 release, great book. It has long piece with notorious Danish publisher who explains the differences of market in a way that "American people want high heels, big boobs and glamour, German people want shit, sm and kiddy stuff, all extreme".. HAHA!! Perhaps merely his empiric study of the 70's porn market from his own experience as published, but still anyone who has ever watched porn, sees the dig differences between countries.
