Those questions are flip sides of the same coin. The problem is defining the boundaries. For example, does it count as an "experiment measuring human behaviour

Those questions are flip sides of the same coin. The problem is defining the boundaries. For example, does it count as an "experiment measuring human behaviour" to slowly roll out a new feature to see if engagement metrics change? What about A/B testing the colour of all the links on your page to see if they're clicked more?