SWOT analysis is a great way to dissect a company and their success model. Take this one for example. This guy dissects Proctor & Gamble according to a SWOT analysis and you can get a good idea of what a SWOT analysis is from this.
SWOT stands for: Strengths, Weaknesses, Opportunities, and Threats. A SWOT analysis is a great, generally accepted, way of figuring out the success and future success of a company. I have used this many times in my marketing classes to find out why some companies are so successful and why some companies are built to have a lot of success in the future.
I think it's important for marketing students to understand what a SWOT analysis is because they will use it later in life when they are working for companies and need to evaluate the direction the company should go or what they are doing right/wrong.