Communicating the vision of the organization, and also its mission, purpose and values is really
important.
One can still find too many firms in which the employees don't even KNOW the vision and mission of their company.
This should preferably be done already at the time the employee joins the organization (during on-boarding), while repeating and refreshing this knowledge occasionally.
But even if an employee is AWARE of the mission and vision of their organization, that still doesn't mean (s)he is actually COMMITTED to it. For that we need to ENGAGE them, creating OWNERSHIP of the corporate vision, mission, values.
On 12manage you can find an amusing story about 3 stone masons and a full discussion on the
importance of communicating the vision and mission. The story makes really clear why it's crucial to ensure that workers not only know the vision, but also carry it in their hearts.