Great article! I have only one comment. I would extend the product strategy definition.

It might not be clear that the goal of the strategy is not only to communicate choices. Strategy acts as a framework for making decisions.

There are also two additional properties worth mentioning:

- Product strategy must be aligned with the business strategy (organization level). In some cases, this may put significant constraints on individual products.

- 'Fit' test as defined by Michael Porter. This is perfectly visible in Microsoft's strategy, in which different products and tradeoffs support each other to create competitive advantage. In my opinion, strategic planning requires analysing company's portfolio, and shouldn't be limited to a single products.

I know that most product people are not interested in business strategy, but I think it's important to make that connection.

Does it make sense?