I recently picked up an old eMac for cheap running Tiger, and when I got it home discovered the mouse was an optical one, and that I must need an optically reflective mousepad of some sort. Years ago I had a Mac Se that I eventually bought an optical mouse for when the mouse that came with the computer wore out. As I recall, that mouse pad had a slick plastic shiny surface ... optimized for reflectivity I guess. Anyway, I was frustrated that the guy that sold me the computer had forgotton to send me the mousepad along with the other hardware. But I thought, heck, I'll just try to run it on the bare surface of my wooden desk and it seemed to work fine. A couple weeks later I found a common mousepad at a thrift store, and thought I'd pick it up to use with my optical mouse as I didn't want to scratch the surface of my desk sliding my new/old eMac optical mouse around on it. It had a nice smooth surface and I thought it would be better than using my bare desk. But I immediately I began to have cursor jumping problems. So I thought, hmmm, maybe I'll try a six inch square piece of thin plywood for a mousepad. And I haven't had a single cursor jump since.