The part of a software application or website that users see and interact with, which takes into account the visual design and the structure of the program. While graphic design is an element of user interface design, it is only a portion of the consideration.

The competitive differentiators that a business has over its competitors.

A site’s total number of users or visitors over a certain length of time. Accuracy depends on each user logging in with a unique username to access the site.

Unique-User/ Device ID is a distinctive number associated with a smartphone or similar handheld device. Device IDs are separate from hardware serial numbers.

Spam or UCE (Unsolicited Commercial Email) is an electronic promotional message sent to a consumer without the consumer's prior request or consent.

When someone permanently removes themselves from your email database.

The way to identify the location for something on the Internet. It is most familiarly in “http:” form, but also encompasses “ftp:” or mailto:

Often used interchangeably with the “address” of a web page, such as http://hackshackers.com. All URLs are URIs, but not vice versa. While humans are familiar with URLs as a way to see web pages, computer programs often use URLs to pass each other machine-readable content, such as RSS feeds or Twitter information. In addition, words that appear in URLs often help boost search rankings, which is why many content sites are now shifting to URLs with headlines as opposed to data strings.

An online tool that reduces the character length of a URL (uniform resource locator) or web address. Commonly used on social media platforms that impose character limits on users’ posts, such as Twitter.

Usability refers to how easy it is for a visitor to your site to use a website in its intended manner. Good usability means that elements such as navigation, content, images, and any interactive elements are easy to use, functioning the way they were intended and that any visitor will not need any special training in order to use the website.

A method of evaluating a website or app’s readiness for release by testing it with real users who are part of your target audience

The path taken by a prototypical user on a website or app to complete a task.

Generally referring to the area of design that involves the holistic interaction a user has with a product or a service. It incorporates many disciplines, including engineering, graphic design, content creation, and psychology. User interface is one element of user experience.