Ars Technica: If you want to use Solaris, from now on, you'll have to pay for it. While Sun used to allow anyone to use its version of the UNIX operating system without support if they filled out a survey, Oracle has modified the licensing terms. Now, you can use Solaris for free for 90 days, and then you must purchase a service contract.
The change does not affect OpenSolaris, the open-source version of the operating system. However, while Oracle has committed to supporting OpenSolaris, it has also said that the open-source version may not have all the same features as the commercial version.