Logarithmic Frequency response graphs

Because it tends to make high frequency irregularities look less significant - good marketing.

Because in order to show the same results on a linear scale, the page would have to be 10 feet wide.

Because there are twice as many frequency/cycles for every octive and the graph repeats every decade so that it is readable. I believe this is a semi-logarithmic graph as the vertical scale is linear.

Human hearing is also perceived in a logarithmic scale.

Thanks for the responses. Let me re-phrase the question a little more specifically.

Why do I usually see freq. response graphed logaritmically between octaves while the ocataves themselves are spaces linearly?