GPL liscence is made to compete with propriatory software, that's why it has the so called "virus-like" behavior. If I contribute to a GPL'ed program I can't turn around and say that this is my program, I have to respect the rights of others who contributed to it. If I was a author of a app that I released as a GPL'ed program I can still sell it to a company to be used in a completely propriatory closed source way I can do that legally, no problem. As long as I am the sole author, if others contribute their code I can't sell their code, because well... It's theirs, I can only sell into closed sourced what is mine. If a company takes a GPL'ed program they can distribute it along with propriatory systems as long as they honor the GPL status and contribute to it just like the original author(s) did. Of course I don't know why it gets this rap about being so restrictive, personally, but others of course feel differently.
BSD code on the other hand can never ever be competative with propriatory software. It's not designed to be. Its more of a academic thing were privite companies can change it or sell it as if they were the ones that created it. In that case the original author has no right to see how his product gets used, just as long as they get a line in the credits. Which ever one you feel like. The reason it cannot be competative in the open market is because if I make a nice program and it's better then a closed source product, then the closed-sourced company can just take it and add the better parts of theirs and mine and make a better program. Meanwhile I have no access to the improvements, which I have to pay for to get just like everyone else.
GPL is only restrictive in the fact that if you a company selling a GPL'ed product then you have to give the source code away. That's it. You can use it for what ever and forever you want it for. Hell you can even charge people for the service fees and the cost of the mediums involved in distributing the code.
however don't get me wrong. I beleive in both types of liscencing scemes and can understand were one may be more advantages in some situations and the other in other situations. There are also several other "free" liscences and such like the one for XFree86 and their are also artistic liscenses for digital art like jpegs and music which are not free, but are perfectly acceptable since they reflect personal expression and such. Their are also some literary liscences and so on and so forth.
Anyways back in the day, BSD was charged with using and distributing code from AT&T type Unix. So they completely rewrote the bits, and basicly redid it. Then they were taken to court and it was basicly dismissed. Later System-V type Unices stole BSD code by using it and not giving them credit. They also did use BSD code and did it legally. If you look
here then it easy to understand how convoluted and how many hundreds of companies and thousands of people contributed to commercial and free versions of Unix. That's why SCO's claim on orignal AT&T IP is such BS, because the the original AT&T code is outclassed and superceded by newer versions such in the way that MSDOS 2.0 was superceded by later versions of Dos and eventually Windows OSes. Exept in the fact that SCO had little to do with the developement and MS did.
Anyways, you just can't take the code from SCO's kernel and graft it into Linux's kernel. They are just to completely alien. Linux may act like Unix to the end-user and most of it is Posix compliant, but it is actually a very very different OS kernel. And the bits that SCO claims they stole Linux actualy predates some of it like SMP support and does better then SCO like large volume support. The future 2.6.0 kernel with pretty much outclass SCO's high-end Unix in every way shape and form. In fact SCO is more expensive and is outclassed by pretty much every other unix variant out there.
SCO it's the only company using BSD code without admitting to it. MS windows also stole BSD code for the TCP/IP protocal stack. They stole it by not giving it credit and changed it enough so that is was slightly incompatable (and fragile/unstable enough) with the the original versions everyone else was using. That's why Bill Gates likes BSD liscence, because he can use it without reprocusions.