During the author's tenure at Reddit, RabbitMQ played a crucial role as the message broker supporting the site's distributed task queue architecture, which allowed for horizontal scalability, flow control, and task scheduling across many servers. This architecture was essential for processing tasks like user actions, such as upvotes, by queuing them before writing to the database; however, it wasn't without its pitfalls, as failures in databases, caches, or the queue processor could lead to data loss. The text highlights the limitations of traditional task queues and introduces the concept of durable queues, which use a persistent store like Postgres to checkpoint workflows, enabling the recovery of tasks from their last completed step and improving reliability. Durable queues enhance observability by maintaining comprehensive records of workflows and tasks, allowing for easy monitoring through SQL queries. The tradeoff with durable queues lies in their reliance on a durable store, which offers stronger data guarantees but lower throughput compared to in-memory stores like Redis, making them suitable for lower volume, critical tasks rather than high-volume tasks.