The three-judge panel of the Ninth Circuit Court of Appeals that has been hearing the Sex.com case has certified the case to the California Supreme Court for a ruling on the legal status of property rights in domain names under California law. The four-year-old case is being brought by the former owner of Sex.com against Network Solutions, which he claims mistakenly transferred the domain's registration to a con artist.
To be precise, the question is under what conditions the tort of conversion ("an unauthorized act which deprives an owner of his property") applies to intangible property like domain names, if at all. Despite what you may have read about the case, no one disputes that domain names are property. Property rights aren't binary; California law has an expansive definition of property that clearly covers domain names. The question is just whether the property right to be secure from conversion covers intangible items that might not even be backed up by a physical document somewhere (as stock certificates are, in theory).
The certification is a routine device used by federal courts (which are required to follow the law of the state in which they sit) to find out what state law says from the court whose job it is to say what that state law is. It looks as though the Court of Appeals thinks that conversion probably does apply to domain names under California law, but was unwilling to say so definitively, since the California Supreme Court hasn't yet touched the issue. The dissenting opinion (by the well-known Alex Kozinski) thinks that the certification is just a waste of everyone's time, since it's so obvious (to him, at least) that domain names are protected.
The full opinions are here