1) Lean microservices can be implemented on OSGi by creating independently deployable services that communicate through OSGi services. This allows for flexible packaging and deployment compared to frameworks like Spring Boot. (2) OSGi supports semantic versioning, remote services, and flexible packaging of modular bundles. (3) A demo chat application shows how different components like an IRC connector, display, and shell integration can be implemented as bundles that communicate through OSGi services locally or remotely.