What is web usability & why is it important?

Web usability is about making your website in such a way that your site users can find what they're looking for quickly and efficiently. A usable website can reap huge benefits on to your website and your business.

• Every £1 invested in improving your website's usability returns £10 to £100 (source: IBM)
• A web usability redesign can increase the sales/conversion rate by 100% (source: Jakob Nielson)

Your website has to be easy to navigate

• Organisation logo is in the top-left corner and links back to the homepage
• The term ‘About us’ is used for organisation information
• Navigation is in the same place on each page and adjacent to the content
• Anything flashing or placed above the top logo is often an advertisement
• The term ‘Shopping cart’ is used for items you might wish to purchase

There are numerous other conventions like these that enhance your website's usability - can you think of some more?

Don't underestimate the importance of these conventions - as the Internet matures we're getting more and more used to things being a certain way. Break these conventions and you may be left with nothing but a website with poor usability and a handful of dissatisfied site visitors.

Pages must download quickly

Usability studies have shown that 8.6 seconds is the maximum time web users will wait for a page to download (source: Andrew B. King - Speed Up Your Site). As of March 2004 just 25% of UK web users had broadband (source: National Statistics) so it's essential for optimal usability that your website downloads quickly.

To speed up the download time of your website we recommend you do three things:

1. Use CSS and not tables to lay out your web page
2. Use CSS and not images to create fancy navigation items
3. Read our article about how to speed up the download time of your web pages

Information should be easy to retrieve

We read web pages in a different manner to the way we read printed matter. We generally don't read pages word-for-word - instead we scan. When we scan web pages certain items stand out:

• Headings
• Link text
• Bold text
• Bulleted lists

Did you notice that images were left out of that list? Contrary to the way in which we read printed matter, we see text before we see images on the Internet. For optimal website usability don't place important information in images as it might go unnoticed.

Restrictions must not be placed on users

Don't prevent your users from navigating through the Internet in the way that they want to. For example:

1. Every time a link is opened in a new window the back button is disabled. Approximately 60% of Web users employ the back button as their primary means of navigation (source: Usability Interface). If you do this then you're preventing 60% of your users from using their primary navigation - now that can't be good for usability.
2. Don't use frames to lay out your website. Frames can cause a number of usability problems, namely:
   • Disabling the back button (see above)
   • Bookmarking not possible
   • Impossible to e-mail the link to someone else
   • Problems with printing
   • Users feel trapped if external links open in the same window
   • Search engine optimisation issues

There are lots of other ways that websites can place restrictions on its users, ultimately damaging their usability - can you think of any more? Just think back to the last time a website really infuriated you - what annoying thing did it do to make you feel that way?

This article was written by Trenton Moss, founder of Webcredible, a web usability and accessibility consultancy. He's extremely good at usability testing and knows an awful lot about accessible CSS web design.