Condé Nast uses machine learning across various applications like recommendations, personalization, advertising, and content understanding. They developed an MLOps platform called Spire to manage the machine learning lifecycle including datasets, modeling, inference, and tracking. Spire includes components like Aleph for feature engineering, Kalos for model training and deployment, and utilizes technologies like Astronomer, Databricks, and APIs to execute workflows and integrate with other systems. Condé Nast aims to improve their platform over time by enhancing models and features as well as consolidating libraries.