[Raven]

Some times, it depends on the fetish or niche.

Someone into domestic spanking may also be into enemas and bondage, perhaps.

Balloon people tend to stick with inflatables and they can be pretty picky, although there can be a cross over into that which is latex....

The smaller the niche, the less likely there will be much of a cross over, though.....

Having said that..to add a bonus section, separate from the content that attracted the member in the first place, is not a bad idea...as long as the bulk of the material inside the site is dedicated to the specific niche.