CDN is content delivery network, a distributed network that serves website assets from locations closer to users.
It matters because development decisions affect speed, security, scalability, tracking, SEO, and maintenance. A site that looks good but is fragile or hard to update can quietly hold back every marketing channel.
Example
Visitors in different regions request the same product image. A CDN can serve cached copies through its distributed network, while the site’s origin remains responsible for uncached or dynamic responses according to the configuration.