In the not-so-distant future, we can expect individuals and businesses to utilize agents and multi-agent systems in the thousands, millions, or even billions, considering the global scale of the Internet economy. The question arises: how will these agents communicate with each other at such scales? Autonomic business ecosystems may evolve to create a wider opportunity for AI-driven marketplaces where businesses and individuals trade services and products through AI agents. This concept of large-scale Agentic Ecosystems is presented in this chapter, and emerging examples are presented in the context of travel and HR domains.