I am more familiar with what Anonymous was trying to say. In the (business) uses I've seen, it means having a big company in a niche industry. It tends to be used somewhat like "it's better to be a big fish in a small pond than another fish in the sea". So, it's better to be the leader of the fold-up bike industry than an also-ran in the generic bike industry.

These "adjectives" are known as "flat" adverbs. It's much like a normal adverb, but it looks like an adjective. Google for "flat adverb" to find more references. However, in some situations you might be able to use a comma to change the sense of the original sentence:

The bombs rested, volatile on the edge of the shelf.

Doesn't quite work in this case, although hopefully you can see where I'm going!