> Depending on how that case finally comes back, I'd expect that could really affect Microsoft's strategy, here
Remember that because there were originally patent claims in the suit, the appeal went to the Federal Circuit -- even though the patent claims were dropped -- not the Ninth Circuit where the district court is located. As a result, the Federal Circuit's ruling that APIs are not uncopyrightable is not precedent since it doesn't concern patents (the Federal Circuit's remit).
Their reasoning might influence future rulings, but precedence-wise the ruling has no bearing on the future of copyright on APIs in the US.
Remember that because there were originally patent claims in the suit, the appeal went to the Federal Circuit -- even though the patent claims were dropped -- not the Ninth Circuit where the district court is located. As a result, the Federal Circuit's ruling that APIs are not uncopyrightable is not precedent since it doesn't concern patents (the Federal Circuit's remit).
Their reasoning might influence future rulings, but precedence-wise the ruling has no bearing on the future of copyright on APIs in the US.
edit: the EFF has a little more detail:
https://www.eff.org/deeplinks/2015/06/bad-news-supreme-court...
https://www.eff.org/deeplinks/2015/06/eff-stands-innovative-...