1. Variety based positioning - based on product/service variety rather than customer segments.
2. Needs based positioning - target a segment with defined needs.
3. Access based positioning - segmenting customers who are accessible in different ways.
To strengthen these positions, Porter believes firms must "trade-off" activities not compatible with the chosen position. This is essential to create the need for choice and limit what the firm offers to customers. Next activities must "fit" and reinforce one another. "Fit" locks out imitators by creating a chain as strong as its strongest link.