What's the difference between regular (aka full), position and short papers?

I've sent the article to the conference and it has been accepted. However, I received a message that my paper has been accepted as the short paper.

I know that there's is a difference in, for instance, the oral presentation time between those 3 kinds of papers. However, I wonder if the type (regular, position, short) can say anything about the quality or the importance of the paper's subject?