In order to penetrate markets, it is essential that high levels of awareness are created as early as possible in a product or brand life-cycle. Hierarchical models provide marketers and advertisers with basic insights about the nature of the target audience, the optimal message and media strategy indicated at different junctures throughout a product's life cycle. For new products, the main advertising objective should be to create awareness with a broad cross-section of the potential market as quickly as practical. When the desired levels of awareness have been attained, the promotional effort should shift to stimulating interest, desire or conviction. The number of potential purchasers decreases as the product moves through the natural sales cycle in an effect likened to a funnel. Early in the campaign, the marketers should attempt to reach as many potential buyers as possible with high impact messages. Later in the cycle, and as the number of prospects becomes smaller, the marketer can employ more tightly targeted promotional activities such as personal selling, direct mail and email directed at those individuals or sub-segments more likely to exhibit a genuine interest in the product or brand.