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This document discusses key concepts in product management including: 1. It summarizes the product lifecycle model and notes that not all products necessarily die, as evidenced by the continued success of the iPad. 2. It outlines the adoption curve model which shows that products have early, middle, and late adopters and that typically only 3.5% of users are innovators who adopt very early. 3. It discusses the concept of market ecology and Gause's principle of competitive exclusion which states that two identical competitors cannot occupy the same space indefinitely in an ecosystem.