Disruption theory, developed by Clayton Christensen in The Innovator’s Dilemma (1997), explains why well-managed incumbent companies lose to new entrants whose initial products are objectively inferior.

Aggregation Theory, developed by Ben Thompson at Stratechery, explains why the most valuable internet-era companies own the user relationship rather than the underlying supply. In pre-internet markets, distribution was scarce and supply control was the strategic asset.

The cold start problem is the chicken-and-egg trap facing every network-effect product at launch: the product has no value without users, and users don’t join products without value.

The atomic network, a framework articulated by Andrew Chen (former a16z general partner, ex-Uber growth lead), is the smallest possible network size that can self-sustain — generate enough internal value that users keep returning even without further marketing inputs.

The Trojan Horse strategy is the market-entry pattern where a startup enters a regulated, network-effect-protected, or entrenched market by first offering a non-threatening “Trojan” product that gets the company in, then expanding the offering toward the real strategic target once inside.

Default alive vs. default dead, Paul Graham’s 2015 essay framework, asks a single question every startup founder should be able to answer: at your current growth rate and burn rate, can you reach profitability before your money runs out?

A North Star Metric (NSM) is the single quantitative measure that best captures the core value your product delivers to customers.

Build-Measure-Learn is the core feedback loop of Eric Ries’s Lean Startup methodology. The cycle: build the smallest viable experiment (MVP), measure customer behaviour against the experiment, learn which hypothesis was validated or invalidated, then loop back into the next iteration.

5 Whys is a root-cause analysis technique developed at the Toyota Production System by Taiichi Ohno. By asking “why” iteratively — typically five times — for any observed problem, the investigator moves past surface symptoms to underlying systemic cause.

The Mom Test, from Rob Fitzpatrick’s book of the same name, is a framework for designing customer interview questions that produce honest signal even when the interviewer’s own mother is the respondent.