That's something that shows you the search terms used by real people to search for specific digital products online like ebook and software. NOT TANGIBLE products like Wii or Ipod.
No, but Google keyword tool is just fine for both digital AND tangible products. I can guarantee for digital products, because all of my websites and blogs feature digital affiliate products, and I used Google keyword tool for most of them, so you can go with that. Alternatively, I am more than satisfied with Micro Niche Finder as a general keyword tool, I bought it long time ago, don't remember the price but I think it's 97$. If you don't have 97$, I have a way to get it for you totally free, PM me if you are interested.