Enterprise systems that require more or less elaborate presentation layers often present challenges to the architects. To understand these challenges, let's take a look at typical implementations. Architects usually consider three main approaches: desktop applications, web applications, and mobile applications. This separation reflects the history of end user technologies. Desktop applications provided much richer functionality compared to the first web applications; browser-based clients could not satisfy most business needs. However, with the advance of the Internet, web applications also changed and browser-based clients became common, delivering intranet solutions for enterprise users. The variety of mobile devices caused a burst of new technologies that created some chaos in the developers' minds for a little while. Even today, if the software vendor does not want to deliver a browser-based mobile application, they still have to develop a few "native" applications...