Your products, online: an eCommerce platform is a web store. It allows your consumers to browse your products complete online purchases via your website.
Customer payments: online stores do not need to include an online payment option directly from the site; in the case of a start-up or smaller business you could choose to invoice your consumers directly and have them pay the amount straight into your chosen bank account via EFT. Of course, it does make more sense to allow a customer to complete their shopping journey with you right on your website.
A business necessity: with more and more online stores launching every day, eCommerce is becoming a necessity for many companies and organisations.
A Content Management System (CMS) is a customised web-based system that is designed to allow clients to manage various aspects of their campaign or user-facing web service. A CMS can provide any functionality required to edit content or features on your user-facing system.
There is little a good CMS cannot do for you. In short, a enables you to be the developer (even if you can do little more than use your computer to send emails)!