An e-commerce website can be hard to maintain, since it should have a large product catalog and a global customer base. That catalog should be searchable, and product pages should contain images, PDF files, customer reviews, etc.
Customers want to find the products they are looking for quickly, and they expect the pages to load fast. The website must provide high availability since worldwide customers want to be able to make purchases at any time, at any place. These requirements are hard to achieve, and it becomes harder as the catalog and customer base grow ...