Hi Brett —
There is a distinction between user acquisition and customer acquisition — and there’s a place for both.
In the customer factory blueprint, acquisition there refers to user acquisition. Using the factory analogy, we treat users as raw materials that we try to convert into customers through our value proposition.
In your case, the leads you capture from your newsletter would be the acquisition step and converting them to subscription would be the revenue event. You can measure a series of activation /retention/steps until that user->customer conversion and, of course post-conversion from deepenning that customer relationship.
Does that clear things up?