To play devil's advocate, I suppose it could be argued this way: If I have made an OS and sell it for $400, then you make copies to give to your four friends, I've lost the $2,000 I would've made had they bought it for themselves.
That is the argument that the software developers use *cough* m$. I think it is a flawed argument. Who is to say that the four friends would have brought it. Lets say none of them because they thought it sucked from what they had been told. However two of them actualy like it. They then go and by a copy of the next upgraded version cuz they liked it that much. End result $800 up.

Thats the only reason i have paintshop pro

By the way Angelic if you gave copies to four of your friends asuming you purchased the original it should be $1600.

That's what is called an off by one mistake and is a common security risk in programming.