Reply to Traktor- How many computers can you put it on?

I want to buy the downloadable version of Traktor but I am worried about the amount of computers you can put it on. Right now I have a Mac, but if I buy Traktor can I also put it on a laptop or a Mac book later on?

Once I purchase it, is there an amount of times you can load it onto another device? Or would I have to keep buying it in order to put it on another device.

If it can be put on multiple devices how do you do that? copy it on a disk and keep loading it put??

Please help, I sent a email to Traktor but It been a week and still nothing..

Thanks Guys.