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?
Jakob NielsenThe usability tests we have conducted during the last year have shown an increasing reluctance among users to accept innovations in Web design. The prevailing attitude is to request designs that are similar to everything else people see on the Web.
Jakob NielsenPopularity is the product of two factors: (a) how compelling material you offer, and (b) how easy it is to access it. Host free pirated movies and users will flock to the site, even if it's difficult to use.
Jakob Nielsen