Illustrator is a vector drawing program. It is often used to draw illustrations, cartoons, diagrams, charts and logos. Unlike bitmap images that stores information in a grid of dots, Illustrator uses mathematical equations to draw out the shapes. This makes vector graphics scalable without the loss of resolution.
Advantages of Vector Graphics
Scalable without resolution loss
Lines are crisp and sharp at any sizes
Print at high resolution
Smaller file size
Good for drawing illustrations
Disadvantages of vector graphics
Drawings tend to look flat and cartoon
Hard to produce photo realistic drawings