I could have sworn this was in the FAQ, but I just checked and it's not. There is no official stance on this from Tom AFAIK. Basically, you can use the registration from the first machine on the second if you want. The software is not supported by licensing or retail sales, only donations. If you feel that a donation is appropriate, that's the answer. If Tom, HK, Brian, etc. know of an official stance, please post and add it to the FAQ...