Elastic Load Balancing (ELB) by Amazon Web Services (AWS) directs traffic to multiple targets, distributing workload evenly among them. It includes Classic Load Balancers, which route traffic to a backend pool of EC2 instances across various availability zones, and Application Load Balancers (ALB), which enhance functionality by allowing routing to multiple ports on the same instance and supporting path-based routing. Monitoring ELB is crucial as it serves as the primary gateway for applications; unexpected issues can lead to overwhelmed targets or application downtime. By integrating with Datadog, users can monitor essential metrics like latency, error codes, and request throughput, and access ALB dashboards to track healthy and unhealthy hosts. Correlating these metrics with other infrastructure data can help diagnose issues, and anomaly detection features can alert users to unusual traffic patterns. Additionally, monitoring ALB latency and response types can provide insights into backend performance, with Datadog's application performance monitoring offering detailed request tracing to identify sources of latency.