lighting - How do I properly do shadowless product photos?

My friend asked me to create a photo like this:

I noticed that its shadowless and my first question is whether it was setup to be shadowless, or was it made shadowless in post? How many lights are involved here? I think there's one for the background, and one above the product pointing something like 30 degrees down, and then some reflectors to the side. Just guessing.

I did some Googling and came across this setup. How could that be shadowless? Looks like the product is a few feet above the ground, which is a white seamless background, and the camera and all the lighting are all pointing down. How could there be no shadow on the ground?

Thanks!

Answer

Also on Digital Photography School, Alex Koloskov walks through creating attractive product photos. And in his blog he shows how to achieve almost the same results with $55 light setup. His blog in general is very educative, as he's professional product photographer who regularly shares the setups used to get the results he got.