New products introduced into the market have a live cycle.  This cycle has been described into four stages; introduction stage, growth stage, maturity stage, and the decline stage.  The introduction stage, as per the textbook, is the intial appearance into the market.  At this point, profits below zero due to the advertisement of the new product, development of the product, and the distribution of the product.  The next stage, the growth stage is where sales grow very rapidly.  Also during this stage, the profits reach a peak point and then they begin to level off, as the competition begins to catch up.  In the maturity stage, the profits continue to decline, in which the competition is most fierce, as many firms have entered the market.  In the final stage, the decline stage, sales have fallen rapidly and the marketers of this product are considering dicontinueing the product line.  The product may no longer be earning a profit for the firm, and a plan to phase it out is being developed, such as using up what is left of the product and then not making any more.