This brings the total number of states allowing same-sex marriage to 24. This refusal effectively eliminates the stays the Court had previously granted which had blocked marriages from taking place in these states. As of early this afternoon, SCOTUS Blog reports that both the Fourth and Tenth Circuits have put their rulings into immediate effect for Virginia, Oklahoma and Utah, but no action has yet been taken in the Seventh Circuit.
These federal circuits also have jurisdiction over six other states with same-sex marriage bans, namely Colorado, Kansas, North Carolina, South Carolina, West Virginia and Wyoming. While the Supreme Court's action does not automatically eliminate these bans, the appellate court decisions finding same-sex marriage bans unconstitutional are binding precedent in the states within the jurisdiction of those courts, so it is widely assumed that they will be struck down in short order.
The Supreme Court's action is viewed as a surprise, as most thought that the high court would be taking action on this issue in this session. SCOTUS Blog offers a full analysis of why this was such a surprising move, including the relatively unprecedented demand from parties on both sides of the issue requesting the Court to weigh in, and the Court's previous action granting stays that prevented same-sex marriages from taking place in the states where appellate courts had struck down bans.
The Fifth, Sixth, Ninth and Eleventh Circuits all currently have cases or decisions pending on this same issue. The action of the Supreme Court provides no binding precedent for these courts.