What is it? 

Web usability is the application of usability to websites - the degree of ease with which users can perform various tasks using a web site interface.

Who cares about it? 

For starters, anyone involved in web design, management, authoring, development, oversight - really anyone involved in making decisions about a website should care about web usability.

And you as a user and consumer of webpages should definitely care!

Why should we care about it? 

Web Usability is not an afterthought, nor an optional "nice to have", it's a "must have". This is true for several reasons:

1. Transactions now made possible via a face-to-face web interface
   The Web is the fastest growing communication medium ever, and it has significantly changed the way we live and work and do business. We now: shop and pay bills online, enrol into university courses online, download forms, submit applications, and make bookings online - transactions we used to carry out in person, face-to-face. And not just a few tech-savvy minority are hoping online and getting connected. [According to ZDNet], it is estimated that 10 million Australians now regularly use the internet for transactions.

   
   The context of online transactions is radically different to the face-to-face business context.

      
   
   There is a two way-communication channel to ensure that you understand what the customer wants...

   
   

   
   
   ...and that the client has understood your response, and is satisfied with your response.

   
   

   
   When it comes to perfominng transactions online, we are held back by limited interactivity and the lack of ability to engage with users through interpersonal communition. The absence of physical presence means that we cannot receive feedback immediately through body language to ensure that the user has understood our response.

              
   
   
   Therefore, it is essential that our web user interface is designed wisely and carefully to act as "the face" and representative of our business.
   

   
   
   [ Images sourced from: www.its.monash.edu.au/staff/web/slideshows/usability-ucd/ ]


2. It makes "people sense" and "business sense".

   In today's internet economy, bad design costs real money in terms of lost sales. If your customers can't find what they want, or they can't complete the purchase when they do find it, it's unlikely that they'll come back a second time. There are far too many other options today.

   And from a users' perspective, good web usability can make the difference between using a website to do a specific task easily, and efficiently and enjoying the process, or being frustrated and not using the site in favour of a friendlier competitor site.

   
   According to Jakob Nielsen:

   On the Web, usability is a necessary condition for survival. If a website is difficult to use, people leave. If the homepage fails to clearly state what a company offers and what users can do on the site, people leave. If users get lost on a website, they leave. If a website's information is hard to read or doesn't answer users' key questions, they leave. Note a pattern here? There's no such thing as a user reading a website manual or otherwise spending much time trying to figure out an interface. There are plenty of other websites available leaving is the first line of defense when users encounter a difficulty.

   [ Extract from Usability 101 by Jakob Nielsen ]

So what are the benefits? 

If customers are happy, they will come again. Furthermore, they might even "put in a good word" and become advocates of the site, enhancing the reputation of the site and in turn increasing the user base.

According to IBM The rule of thumb is: