Usable. Ease of use remains vital, and yet the interface-centered methods and perspectives of human-computer interaction do not address all dimensions of web design. In short, usability is necessary but not sufficient.

Desirable. Our quest for efficiency must be tempered by an appreciation for the power and value of image, identity, brand, and other elements of emotional design.

Findable. We must strive to design navigable web sites and locatable objects, so users can find what they need.

Accessible. Just as our buildings have elevators and ramps, our web sites should be accessible to people with disabilities (more than 10% of the population). Today, it’s good business and the ethical thing to do. Eventually, it will become the law.

Credible. Thanks to the Web Credibility Project, we’re beginning to understand the design elements that influence whether users trust and believe what we tell them.

Valuable. Our sites must deliver value to our sponsors. For non-profits, the user experience must advance the mission. With for-profits, it must contribute to the bottom line and improve customer satisfaction.

• Keep action sequences consistent in similar situations.
• Use identical terminology in prompts, menus, and help screens.
• Employ consistent commands throughout.

Enable frequent users to use shortcuts.

• As the frequency of use increases, so do the user’s desires to increase
  interaction speed.
• Abbreviations, function keys, hidden commands, and macro facilities are very
  helpful to an expert user

Offer informative feedback.

• System feedback should be provided for every operator action.
• Frequent and minor actions can provide a modest response, while the response
  should be more substantial for infrequent and major actions.

Design dialog to yield closure.

• Organized sequences of actions into groups with a beginning, middle, and end.
• Informative feedback when a group of actions is completed, gives the
  operators a sense of accomplishment and an indication that they can proceed to
  the next group of actions.

Offer simple error handling.

• The system should be designed so the user cannot make a serious error.
• If an error is made, the system should be able to detect the error and offer
  simple, comprehensible ways to recover from the error.

Permit easy reversal of actions.

• If the user knows that errors can be undone, they are encouraged to explore
  unfamiliar options without undue anxiety.
• The units of reversibility may be a single action, a data entry, or a complete
  group of actions.

Support internal locus of control.

• Experienced operators like to sense that they are in control of the system and
  that the system responds to their actions.
• Design the system to make users the initiators of actions rather than the
  responders.

Reduce short-term memory load.

• Displays should be kept simple and sufficient training time should be allotted
  for codes, mnemonics, and sequences of actions.

5 attributes of Usability:

1. Learnability: The user should be able to promptly start performing their tasks with the system.

2. Efficiency: Once the user has learned the system, a high level of productivity should be possible.

3. Memorability: The casual user should be able to return to the system after not having used it for some time, without having to relearn everything.

4. Errors: Users should not make many errors using the system, and if they do, they should be able to easily recover from them. Catastrophic errors should not occur.

5. Satisfaction: Users should like using the system and should be subjectively satisfied when using it. The system should be pleasant to use.

Eye tracking is the process of measuring either the point of gaze (”where we are looking”) or the motion of an eye relative to the head. eye tracking monitor records every eye movement and highlights the most active areas on the site visually. Eye-tracking studies can help to estimate how comfortable web users are with the web-site they’re browsing through and how quickly they can understand the structure and system behind it. You can find some interesting usability findings from recent eye-tracking study.

Fold

The fold is defined as the lowest point where a web-site is no longer visible on the screen. The position of the fold is, of course, defined by the screen resolution of your visitor. The region above the fold (also called screenful) describes the region of a page that is visible without scrolling. Since the fold is seen directly without scrolling, it is often considered as the area which guarantees the highest possible ad click rates and revenues. However, Fold area isn’t that important.

Foveal viewport (Foveal area)

The fovea, a part of human’s eye, is responsible for sharp central vision, which is necessary in humans for reading, watching television or movies, driving, and any activity where visual detail is of primary importance. Foveal area is a small wide space area where your eyes are aimed at and it is the only area where you can perceive the maximum level of detail. Foveal area is a tight area of about two degrees of visual field or two thumbnails held in front of your eyes. This is the place where you’d like to deliver the most important messages of your visitors.

Foveal viewport is important, because outside of this wide screen area how your visitors see your web-pages change dramatically. Inside this area is the only part of your vision with the maximal resolution – only here no eye scanning is necessary.

Gloss

Gloss is an automated action that provides hints and summary information on where the link refers to and where it will take the user once it’s clicked. Hints can be provided via title-attribute of links. From the usability point of view users want to have the full control over everything what is happening on a web-site; clear and precise explanations of internal and outgoing links, supported by sound anchor text, can improve the usability of a web-site.

Graceful Degradation (Fault-tolerance)

Graceful Degradation is the property of a web-site to present its content and its basic features even if some of its components (partly or at all) can’t be displayed or used. In practice it means that web-sites display their content in every possible “fault” scenario and can be used in every configuration (browser, plug-ins, connection, OS etc.) the visitor might have. “Power-users” are still offered a full, enhanced version of the page. For instance, it’s typical to offer alternatives for Multimedia-content (for instance image) to ensure that the content can be perceived if images can’t be displayed.

Granularity

Granularity is the degree to which a large, usually complex data set or information has been broken down into smaller units.

Hotspot

Hotspots are clickable site areas which change their form or/and outer appearance once they are clicked. This is typical for :focus-effects when a link or any other site element is clicked.

Legibility

Legibility indicates how clear the text is visually.

Minesweeping

Minesweeping stands for user interactions which aim to identify the links on a web-site. In most cases minesweeping is a clear alarm signal for usability problems. Usually minesweeping involves the user rapidly moving the cursor or pointer over a page, watching to see where the cursor or pointer changes to indicate the presence of a link.

Mystery-Meat Navigation (MMN)

In Web mystery-meat navigation describes designs in which it is extremely difficult for users to recognize the destinations of navigational hyperlinks — or determine where the hyperlinks are.

Physical consistency

This concept describes the consistent outer appearance of a web-site – e.g. the position of logos, navigation, the use of graphic elements and typography. Physical consistency is essential for better orientation and effective site navigation.

Progressive Enhancement (PE)

Progressive Enhancement is a design strategy in which sites are created in a layered fashion — from the basic functionality for all browsers to the additional, enhanced features for modern browsers. The main advantage of progressive enhancement lies in its “universal usability” — i.e. the fact that it allows everyone to access the basic content and functionality of a web page, using any browser or Internet connection, while also providing those with better bandwidth or more advanced browser software an enhanced version of the page.

Readability

Readability describes the degree to which the meaning of text is understandable, based on the complexity of sentences and the difficulty of vocabulary. Indexes for readability usually rank usability by the age or grade level required for someone to be able to readily understand a reading passage. Readability is not legibility.

User-centered design (UCD)

User-centered design is a design philosophy in which users, their needs, interests and behavior define the foundation of web-site in terms of site structure, navigation and obtaining the information. UCD is considered as a standard approach for modern web-applications, particularly due to the rise of user generated content. In Web 2.0 visitors have to be motivated to participate and therefore need conditions optimized for their needs.

Vigilance (sustained attention)

Vigilance is the ability to sustain attention during prolonged, monotonous tasks such as proofreading a text looking for spelling errors, reminding of appointments, auto-saving word processor documents etc. In modern web-applications vigilance tasks are performed in background, automatically and thus improve the usability of the service.

Walk-Up-And-Use Design

A Walk-up-and-use design is self-explanatory and intuitive, so that first-time or one-time users can use it effectively without any prior introduction or training.

Wireframe

A wireframe is a basic structure — skeleton — of a site that describes the ideas, concepts and site structure of a web-site. Wireframes can be designed as presentations which explain to the stake holders how the site is designed, which functionality it offers and how users can accomplish their tasks. Wireframes usually don’t have any visual elements or a complete page layouts; they are often first drafts and sketches designers create on paper. Example? Here you go.

2xx: Successful

3xx: Redirection

4xx: Client Error

5xx: Server Error