Web site usability is defined as the effectiveness, efficiency, and satisfaction with which users can achieve tasks in a particular environment. High usability means a system is easy to learn and remember.

The challenge is to design a website that allows access to the important features without cramming them all on to the homepage. Focus and clarity are key, as is an understanding of users' goals. The goal of most websites should be to make it easy for visitors to perform useful tasks and find information they find pertinent.

The field of web usability has matured sufficiently that specialized guidelines to codify the best design practices for specific components of a website have now been developed.

Below are 62 web usability guidelines for the sites that we use for our clients. As you read through these guidelines you will undoubtedly feel that adhering to all guidelines is extremely difficult. The "perfect website" will probably follow 90-95% of them. If you decide not to follow a certain guideline do so based on verifiable data and consistent user feedback.

Communicating the site's purpose:

• Show the business name and/or logo in a reasonable size and location. Upper left corner is usually the best.
• Include a tag line that explicitly summarizes what the site is all about. Keep tag line short, simple and to the point.
• Emphasize what your site does from a user's point of view. Give the visitor what they want in an easy way.

Communicating Information about your business:

• Group company information such as About Us, Job Openings, and other general items in one distinct area.
• Include a link on the home page to an "About Us" section that gives the visitor clear, detailed information about your company and the services it provides. The recommended name for this link would be About [company name].
• Present a unified design for your web site that coincides with the look and feel of your offline branding/marketing materials.

Content Writing:

• Use "customer-focused" language. Label sections and categories according to the value they hold for your users.
• Don't use clever phrases or "lingo" that make people wonder or work too hard to figure out what you're saying.
• Use examples to reveal the link contents rather than just describing it. Instead of saying "Get all of today's headlines" show the top 5 headline for that day and link them to the full story.

Links and Navigation:

• Begin links with information-carrying words but keep them brief. Use words and language that have meaning to your users. Most of all make your links and navigation area easy to scan.
• Allow link colors to show visited and unvisited states. Also it is better to have your links begin with an underline and have the mouse over affect remove the underline than it is the other way around.
• If a link does anything other than go to another web page, such as a PDF file, audio file or video file, make sure the link explicitly indicates what will happen when the visitor clicks that link.
• Offer users direct access to high-priority/highly sought after tasks on the homepage. Give users the content they most want right on the homepage or access to it with a single click.

Graphic Design and Animation:

• Use graphics to show real content, not just to decorate your homepage.
• Don't use animation for the sole purpose of drawing attention to an item. Animations are often ignored by users because they look like ads. Never animate critical elements like logos, taglines or headlines. Animations are best used to show a procedure that is easier seen than described. Provide a way to turn animations off when you do use them.
• Use high contrast text and background colors that make text as legible as possible.
• Avoid horizontal scrolling at 800 x 600 resolution.

Miscellaneous:

• Be sure to create titles for each of your windows. Titles should use information-carrying words and include the business name. Don't use domain name extensions like ".com" in your window titles. Don't use the word "homepage" for you homepage window title. Limit window titles to 7 or 8 words and fewer than 64 characters.
• Make your domain names (URL) reflective of your company name and easy to remember. Don't use characters like hyphens in your URLs. Register alternative versions of your URL, if there are common misspellings register those and re-direct your users to the main URL. Register the .org, .com and .net versions of your domain name.
• Avoid pop-up windows. Using extra windows to display important information has a draw back in that once the user clicks off the pop-up it is hidden and they may not be able to get it back if they click that link again. If you do use pop-ups do it judiciously and tell your users that clicking that link will open a new window.
• Avoid using statements like "Best viewed with Internet Explorer 4.x or greater". Typically users will not upgrade their browsers to view your site. It is better to be sure that your site works well in the widest array of browsers and platforms that your visitors tend to use. If you decide to stop support a particular browser or version use a detection script that determines the browser a visitor is using and then sends them to a page that indicates their current browser will not work with this site.

Credits
   This page was developed and adapted based on the research, books and web sites by Dr. Jackob Nielsen.

Homepage Usability - 50 Websites Deconstructed
Jakob Nielsen and Marie Tahir
Copyright 2002 by New Riders Publishing

Designing Web Usability
Jakob Nielsen
Copyright 2000 by New Riders Publishing

Website: http://www.useit.com