It took European regulators nine years to win their titanic antitrust battle against Microsoft. Other companies are likely to feel the implications a lot more quickly.

Legal experts say the rebuke of Microsoft by the European Court of First Instance (the second-highest court in the European Union) is a resounding victory for the European Commission. It also paves the way for regulators there to take a much more muscular approach both to antitrust issues and to corporate compliance generally.