In economics, a service is a transaction in which no physical goods is transferred from the seller to the buyer.

The benefits of such a service are held to be demonstrated by the buyer's willingness to make the exchange.

Public services are those that society (nation state, fiscal union, region) as a whole pays for.

Using resources, skill, ingenuity, and experience, service providers benefit service consumers.

Web design encompasses many different skills and disciplines in the production and maintenance of websites.

The different areas of web design include web graphic design; interface design; authoring, including standardised code and proprietary software; user experience design; and search engine optimization.

Often many individuals will work in teams covering different aspects of the design process, although some designers will cover them all.

The term web design is normally used to describe the design process relating to the front-end (client side) design of a website including writing mark up.

Web design partially overlaps web engineering in the broader scope of web development.

Web designers are expected to have an awareness of usability and if their role involves creating mark up then they are also expected to be up to date with web accessibility guidelines.

In sales, commerce and economics, a customer (sometimes known as a , buyer, or purchaser) is the recipient of a good, service, product or an idea - obtained from a seller, vendor, or supplier via a financial transaction or exchange for money or some other valuable consideration.

An ultimate etymology of "client" may imply someone merely to do business, whereas a purchaser procures goods or services on occasion but a customer customarily or habitually engages in transactions (historically: the collection of tolls or taxes - see ).

Such distinctions have no contemporary semantic weight.

A system is a set of interacting or interdependent component parts forming a complex or intricate whole.

Every system is delineated by its spatial and temporal boundaries, surrounded and influenced by its environment, described by its structure and purpose and expressed in its functioning.

Online shopping is a form of electronic commerce which allows consumers to directly buy goods or services from a seller over the Internet using a web browser.

Consumers find a product of interest by visiting the website of the retailer directly or by searching among alternative vendors using a shopping search engine, which displays the same product's availability and pricing at different e-retailers.

As of 2016, customers can shop online using a range of different computers and devices, including desktop computers, laptops, tablet computers and smartphones.