A couple of very interesting posts on Eric Schrock's Weblog
First about the GPL in GPL thoughts and clarifications. I wonder which licenses Eric is thinking of in his #2 (LGPL is the nearest I can think of but it looks like he means more finely grained than that).
Secondly on the "competition" with Linux, why Solaris is different and can stay so in Rebutting a rebuttal which is a response to a number of attacks such as linux kernel monkey log: A rebuttal of a single Sun misinformed developeron his earlier post Analysts on OpenSolaris.
As someone who has happily and successfully used linux for 6 years but never used Solaris I have to agree with Eric. There is definately room for another open source unix, one that has a slightly different license and which has different priorities.
I would completely accept that at the moment Solaris has a number of significant advantages over linux in demanding environments (for scalability, security and reliability). Linux has advantages in hardware support and in lightness (I don't see Solaris on any PDA's or embedded in firewalls or games machines). For most businesses Linux goes plenty far enough in security etc - but there are some where it does not. Anyway choice is a good thing.
The problem I can see for Solaris is much more long term. True Sun may not have the resources/motivation to port their code into Linux. But if Eric's thoughts on the license happen then, in the long term, Linux can take on all the cool bits of Solaris but Solaris cannot take things from Linux. Therefore while the gap may never disappear it will get smaller and smaller.
Even if the gap between Linux and Solaris did completely disappear in several years time (my guess is that it won't but the sell of the gap will become non obvious and for more industries less important) that will not necessarily be a disaster for Sun. They will still be able to sell on engineering principals that reduces a companies need to test and validate new releases themselves. Companies will still find it easier to get the security/reliability some of them need from Sun who will have much greater control over Solaris than RedHat etc have over Linux. Again that will not matter to most but those for whom it does matter will still be a lucrative place for Sun (but a Sun of the present size is less clear).
I suppose the key difference is that Linux will continue to exist and move forward even if the world economy collapses, Solaris will still require Sun as a financially sound parent for it's continued development (because without the engineering (development ands support) strength of Sun the advantages of Solaris disappear).
If I was employed by Red Hat I would be worried about this, but even more so if employed by Microsoft who I guess are deliberately not being mentioned by Sun just yet but are attacked by so many Sun products (Solaris, SunRays, OpenOffice.org, Java, solutions for the financial industry etc) which are starting to look like stronger competition to Microsoft products than anyone has been for many years.