I use a thermal insulating pad, and I have for years, but I hadn't realized such damage could be caused. I did it because it was just too darn hot to comfortably have sitting on my lap for more than a few minutes.

Newer laptops, notebooks and netbooks are supposed to have cooled down considerably under there but I would still use a pad, because it's more comfortable. There are a lot of laptop coolers but most of these still need to have a free flow of air underneath so they can dissipate heat and so really have to be put on a flat surface like a desktop or airline tray; thermal pads should also have a passive way to allow trapped heat from your body to escape, like padded, raised legs, but they pretty much stop heat from the computer migrating downward and staying in contact with your skin.