The product vision describes the future we are trying to create, typically somewhere between two and five years out. For hardware or device‐centric companies, it's usually five to 10 years out.
Note that this is not the same as the company mission statement. Examples of mission statements are “organize the world's information” or “make the world more open and connected” or “enable anyone anywhere to buy anything anytime.” Mission statements are useful, but they don't say anything about how we plan on accomplishing that. That's what the product vision is for.
Note also that the vision is not in any sense a spec. It's mainly a persuasive piece that might be in the form of a storyboard, a narrative such as a white paper, or a special type of prototype referred to as a visiontype.
Its primary purpose is to communicate this vision and inspire the teams (and stakeholders, investors, partners—and, in many cases, prospective customers) to want to help make this vision a reality.
When done well, the product vision is one of our most effective recruiting tools, and it serves to motivate the people on your teams to come to work every day. Strong technology people are drawn to an inspiring vision—they want to work on something meaningful.
You can do some amount of testing of the vision, but it's not the same ...