White faces while editing mesh

I have seen a couple posts about white faces, but they are all about textures and UV.

I am learning to work with meshes and I frequently run into these white faces. What do they mean? I can’t figure out how they get there and how to get rid of them.

Attached is a screen shot with normals showing.

Is this meaningless, or will it pose an issue later in the process?
Thank you!
B (Blender 2.53 Mac osx)

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