Histogram clipping

I understand the histogram in terms of right and left (overexposed and underexposed), but what does it mean when your curve clips at the top of the graph into a plateau? Is this a limitation of the graph itself or do I need to compensate my camera settings?

thanks,
Ken

That's not a problem. It just means there are a lot of pixels that have approximately the same color. It doesn't mean something is over- or underexposed or that you have to adjust something on your camera.

Thanks Jesper for the explanation.
So if I have two similar photos with similar curves with the difference being that one clips at the top and the other doesn't, is it correct to assume that the one with the clipped histogram has 'better' saturation? Or does saturation have nothing to do with this and I should just ignore clipping from this point forward?

I tried to take 4 similar shots of a given subject using both a 2.8 lens and a 3.5 lens, both at 4.5 aperture at 70mm, with and without a hood.
For the 3.5 lens, the histogram clipped only in the hoodless shot. For the 2.8 lens, it clipped in both. Granted, this was not a great test since I didn't use a tripod.

The Y axis of the histogram tells you how many of the pixels in the image fall within the gray shade shown in the X axis. So, the taller that curve at a given gray point, the more pixels there are with that exact gray shade. If there were no pixels in a particular gray shade, then the curve at that point would be at 0 or touching the bottom axis.

I don't think you'll be able to determine the saturation of the image directly from the histogram.