Teamwork is a collection of people who respect each other and are committed to each other's successes, according to Hank Sydor.
When you attend a seminar or conference, they usually include one session on "team-building." The conference leaders also usually go through the now familiar routine of "introduce your self to the people next to you," or they put you into teams to solve a problem that is presented to you as a group. The other thing that is common is a couple of cheerleading exercises that they use as a fundamental way of promoting teamwork within your corporate structure.
While some of these activities are plain hokey, the concept of having everyone working together is critical to the success of every business. What is even more important is the ability to work with different groups and not only your "team."