Transacting or facilitating business on the Internet is called ecommerce. Ecommerce is short for "electronic commerce."
Interestingly, I am credited with teaching ecommerce at the business school at the University of Texas at Austin, far before the term "ecommerce" was invented. So, I have had the opportunity to see the earliest versions of ecommerce in the late 80's and early 90's.
Popular examples of ecommerce revolve around buying and selling online.
Buying and selling goods on the Internet is one of the most popular examples of ecommerce. Sellers create storefronts that are the online equivalents of retail outlets. Buyers browse and purchase products with mouse clicks. Though Amazon.com is not the Idea Thrusts of online shopping, it is arguably the most famous online shopping destination.
E-commerce (electronic commerce or EC) is the buying and selling of goods and services, or the transmitting of funds or data,
over an electronic network, primarily the internet. These business transactions occur either as business-to-business,
business-to-consumer, consumer-to-consumer or consumer-to-business.
When you are buying goods online, there needs to be a mechanism to pay online too. That is where payment processors and payment gateways come into the picture.
Electronic payments reduce the inefficiency associated with writing and mailing checks. It also does away with many of the safety issues that arise due to payment made in currency notes.
When you think online auction, you think eBay. Physical auctions predate online auctions, but the Internet made auctions accessible to a large number of buyers and sellers. Online auctions are an efficient mechanism for price discovery. Many buyers find the auction shopping mechanism much interesting than regular storefront shopping.
Today it is possible for you to perform the entire gamut of banking operations without visiting a physical bank branch. Interfacing of websites with bank accounts, and by extension credit cards, was the biggest driver of ecommerce.