Ideally, after writing marketing plans for a few years, you can sit back and review a series of them, year after year, and check the progress of your company. Of course, sometimes this is hard to make time for (;there is that annoying real world to deal with);, but it can provide an unparalleled objective view of what you've been doing with your business life over a number of years.
Rallying point: Your marketing plan gives your troops something to rally behind. You want them to feel confident that the captain of the vessel has the charts in order, knows how to run the ship, and has a port of destination in mind. Companies often undervalue the impact of a "marketing plan" on their own people, who want to feel part of a team engaged in an exciting and complicated joint endeavor. If you want your employees to feel committed to your company, it's important to share with them your vision of where the company is headed in the years to come. People don't always understand financial projections, but they can get excited about a well-written and well-thought-out marketing plan. You should consider releasing your marketing plan--perhaps in an abridged version--companywide. Do it with some fanfare and generate some excitement for the adventures to come. Your workers will appreciate being involved.