*When the polygon is viewed directly from above (so that it appears flat or parallel to the screen, for instance), the common standard is that the points are arranged in a counter-clockwise direction. The normal is then facing directly at you. If they are ordered in a clockwise fashion, the normal points directly away from you.*

The classic way to remember this is the "right-hand rule." If you curl the fingers of your right hand in the direction the points are going, your thumb will be pointing along the normal. (If you look in on a bunch of engineering students taking a test, you'll often see them curling their hands this way.)

But if you're not interested in vector math, all you need to know is that reversed normals means you're looking at the back side of the polygons. Poser 4 is more tolerant of reversed normals than Poser 5. Some things that look fine in P4 have ugly black splotches in Poser 5. It's usually reversed normals.

And if you import an object made in another app, and it looks black no matter what texture you apply, try importing it again, with "reversed normals" checked.