Usability (literally “useability”, “ability to be used”, “utility”) is a concept in micro-ergonomics, indicating the final level of object convenience for use in stated purposes. The term has a connection with the concept of “ergonomics”, but unlike the latter, it is less associated with technical aesthetics, with appearance and is more tied to the utilitarian nature of the “usable” object. (from Wikipedia)
In simple terms and in our context, Usability is the level of convenience of a service on your web resource or the entire resource as a whole. To assess this level, a number of technologies are used, from interviewing and creating all sorts of focus groups, hot-maps, using various statistics services, allowing you to determine the behavior of users on your site.
The set of actions described above is called usability audit or usability testing and, in fact, is an experiment conducted to assess the level of usability of your resource.
The result of usability audit is the refinement of the resource-object in order to increase the number of conversions of ordinary visitors to the resource in effective users (customers, customers, subscribers, etc.).
At its low cost, this procedure can significantly increase the level of profitability of the resource. When carrying out works on complex website promotion it is recommended to audit several times, because search engine optimization of sites and contextual advertising are tools of attraction of a target audience on your site, and works on increase of usability will help to increase number of returns and orders on your resource.