This document discusses Porter's Five Forces framework for analyzing industry competitiveness and attractiveness. Porter's Five Forces include: the threat of new entrants, bargaining power of buyers, bargaining power of suppliers, threat of substitutes, and competition within an industry. These forces determine the structural determinants of industry attractiveness and help shape corporate strategy. The document also briefly discusses different models of open access academic publishing including gold, green, and diamond open access models and what would be needed for a disruptive diamond open access model.