Good ruling, but weird reasoning.

I would have thought the reasoning should be that in a legal system based on the rule of law, people need to be notified and able to inform themselves of which laws exist and apply to them. The source in the text of the US Constitution for this idea could be in the part about depriving people of liberty without due process of law.

If a company has no way of knowing or exercising control over whether users are accessing its services from Utah, how can Utah apply any of its state laws to that company?