What is a crypto pump signal group?

Could you elaborate on the concept of a "crypto pump signal group" in the cryptocurrency sphere? Are these groups specifically designed to provide investors with timely signals or indications of potential upward price movements in certain cryptocurrencies? Do they operate through a centralized platform or are they more decentralized, relying on social media or other channels for communication? Are they typically composed of professional traders or enthusiasts who share their insights and analysis? And most importantly, how reliable are these groups in accurately predicting price pumps, or is it more of a speculative endeavor?