California’s Proposition 8 case was rejected by the Supreme Court based on standing. This is an important legal term meaning the man who filed the appeal had no basis for doing so because he wasn’t affected by the law. The ruling means the Court couldn’t rule on the constitutionality of marriage because the party bringing the action had no legal basis for doing so.
It means also that the Ninth Circuit had no basis for deciding the case so the decision of the state court stands making marriage equality the law in California. This is a win for the LGBT community in a flawed case which prevented a landmark decision affecting the entire country.