The extent to which an item is capable of being used, or is convenient and practical in use. (Wikipedia)

Usability is one of those areas of web development which is extremely important, extremely obvious when you look at it; and easily overlooked if you’re not actively looking for it. It’s simply the question of whether the site is easy to use. Are the features which are needed present is a common question. From a usability perspective, the question becomes “Are the features which are needed present, easy to find, and easy to understand?”

It’s a subtle difference; but a crucial one.

The fundamentals of usability

When you come right down to it, one of the most basic issues for web usability is whether the interface is similar to interfaces the user has seen before. There are certain standard paradigms of web interface design in how navigation is presented, where it’s located, and what it does. There are expectations formed by thousands of web site interactions which lead users to quickly and easily understand similar interactions. Designers frequently want to “break out of the box” — this is fine, but only as long as they understand and prepare for the risks.

In addition to maintaining a common structural paradigm, usability requires developers to anticipate the user’s needs. To take a basic web site login as an example, good usability requires that the web site:

  1. Is easy to find.
  2. Provides easy access to recover lost passwords.
  3. Provides easy access to recover lost usernames.
  4. Informs the user of the advantages of registration.
  5. Provides the option to be remembered; so that they don’t have to log in every time.
  6. Notifies the user of your use of their private data whether you use it or not.
  7. Makes it easy for the user to be aware whether they are currently logged in.
  8. Makes it easy for the user to log out, if they are.
  9. Gives users the ability to change their registration information, such as registered email address, user name, or password whenever they wish.

These features aren’t absolutely necessary to have a functional registration and log in system: but they will make the system significantly easier to use and more successful for the customer.

Usability also extends to the structure of the page as a whole. Huge, long blocks of text are more difficult to follow and read — breaking them up into sections delineated by headings, lists, and images can make the document as a whole much easier to digest.

Usability is a broad issue for web interface design. But if you’ve ever encountered a web site which consistently frustrated you because information was difficult to find or the navigation structure was obtuse, then you’ve seen what a lack of usability focus can do. One of the greatest challenges with usability is to make every website unique while continuing to exhibit all those common characteristics which users have come to expect. Considering usability throughout the design of your site can make a huge difference in making sure your end product meets everybody’s needs in design and function.