In the beginning, of Graphical User Interfaces (GUI) at least, all applications used a thick (or fat) client. That means the client controlled all aspects of the user experience in regards to using an application. Developers tended to like them because they allowed them to provide a generally richer experience and better control of said experience. As Web browsers matured, though, enterprises began pushing developers for Web (or thin) clients. That is because thick clients normally required a visit by a desktop technician and keeping up with the versions was very difficult.
Fast forward to today. Today, we have multiple browsers and multiple versions thereof. Furthermore, the browser developers are pushing out new versions faster and faster. Now, we have a very difficult situation for the enterprise to manage. Thin client X required browser version N where thin client Y requires browser version N+1. If a user needs to run both, we have a real problem. This leads to pressure by enterprises on developers to keep up with the browser versions.
I believe this will lead to the return of the thick client. I am already seeing some of this. LogMeIn, which is remote desktop software, used to be all browser based. It now requests to load a thick client when you select to remote control. It downloads and installs said client with your permission. I also am working with Forms inMotion from Keymark. It currently only has a thick client though a Web client is on the horizon.
Why can this work now when it didn’t previously? Well, first, there is more bandwidth now making downloading and install on demand more viable. There is still the potential problem of needing admin rights to install that needs to be licked though. Second, software like LanDesk (link taken down at their request) allows enterprises to originally install software without a desktop technician visit and keep it up to date.
The bottom line is I believe we will see the return of the thick client.