The World of Goo Corporation is a metagame, where the objective is to build a tower as high as possible. The number of goo balls is based on the best number of goo balls rescued: you receive one goo for each extra goo that you rescued; rescuing the minimum doesn't give any bonus.
Within the World of Goo corporation, you are given a set of Goos which will attach to two other goos (or can otherwise form an extra link between two other Goos.) You can detach goos at any time.
The objective is to create a tower as high as you can, starting with a single triangle. As you build the tower, you will see clouds showing the hight of other players. The arena expands infinitly in any direction, but the most important direction is up.
As the tower grows, be careful if it begins to lean to one side; when it does, you will have to spend time rebuilding the tower. To fix leaning issues, either reinforce the side it is leaning on, or add a counter-weight before it collapses.