– The set of usability standards – it represents perceived ease of use and perceived usefulness; the first is defined because the degree to which a person considers using a specific system is freed from effort, whereas the latter refers to the degree to which one thinks that resorting to a specific system enhances one’s performance. With the intention to assess the extent of usability the next notions must be considered: accessibility, compatibility, functionality, person’s satisfaction, user interface. All these characterize belongings of the usability principle. Within the area of e-health services, these notions are utilized to the applied sciences …