I confess, I didn't see this coming: California votes yes on Proposition 8. I do think, though, that the success of anti-gay-marriage initiatives reinforces something I strongly believe: the issue was pressed too quickly, and in the wrong venue. Using the courts to establish a right to gay marriage made opponents feel threatened, and railroaded. If socially conservative voters hadn't felt they needed to protect themselves from activist judges, we wouldn't be seeing these provisions written into state constitutions. Few of them would probably have bothered to vote out legislators who voted for gay marriage five years from now. But with it on the ballot, in front of them, and worries that judges would make the decision unless they did, they shot it down even in California.
In general, courts are the wrong place to press these sorts of claims. The courts were appropriate for civil rights because blacks were literally denied the right to participate in the legislative democratic process. And on a practical level, they worked becaus a majority of people in the country were more than happy to force civil rights on an unhappy white southern minority. Unfortunately, too many groups have decided that the success of civil rights can be widely applied to circumvent the electorate on issues where there is no public consensus. Now widespread gay marriage seems quite a bit less likely for the near term than it would have been had we attacked the issue legislatively.