Most people can benefit from adjusting their monitor in order to view online photos better. Here are two web pages that help you do this:
- Step wedge adjustment - a simple adjustment that can improve the photo looks a lot. You should be able to see each of the shades of gray.
- Monitor Calibration - Stanley Rowin Photography. This page includes a step wedge with even more intermediate shades of gray, making finer adjustment possible.
Also note that Stanley Rowin's page mentions that the gamma adjustment part of his page doesn't work for most flat panel monitors.