Clojure's three killer design decisions that boosted its adoption and maturity were:
1) Solving everyday problems through its small core and terse syntax which addresses boilerplate code and provides primitives for concurrency and parallelism.
2) Being hosted on the JVM to leverage the trusted and performant runtime as well as the large Java ecosystem.
3) Having effective governance through significant innovations within the first 10 years and an openness to adopting ideas from other communities.
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