A CDN distributes web content via global edge servers to enhance website speed, scalability, and security. By caching static assets and routing user requests to the nearest server, CDNs reduce latency and bandwidth usage. Key benefits include faster load times, DDoS protection, SEO improvement, and reduced server costs. Selecting the right provider depends on coverage, performance, and security needs, with popular options like Cloudflare and Akamai. Implementation involves DNS configuration, caching rules, and performance monitoring. Best practices include optimizing cache policies, enabling HTTP/2, and avoiding common pitfalls like stale content and SSL errors. CDNs are essential for sites with global reach or traffic spikes, and offer value for businesses of all sizes.