Visual consistency is necessary because it allows the users to bring some credibility to your brand or company. It also has an impact on the ergonomics of the site (ease of use). But attention, consistency does not mean enuyeux. The goal is no longer not to lull your users.
The graphic design is the reference of the brand or business tool. You will well understand, it is a model of consistent pages.
In summary, a graphic Charter imposes certain rules to strengthen consistency while allowing some flexibility in the expression of the content.
At the beginning of the Internet, it simply transposed the print (print) web site at the expense of ergonomics. This trend was reversed. It is the creation of the web site that will influence the design of printed media.