Every point of friction the user encounters when trying to use a product is point where they will stop and do something else. Desktop software is too difficult to try out. People are scared of spyware. Configuration and system compatibility can be a huge hassle. Under Vista, there are a zillion security warnings to click through. And in business environments, computers are often locked down. Forcing users to go through that just to try your product will turn off the majority of your site visitors, resulting in much lower sales.
Another key factor is that with web based software you can do continuous releases, which is key in a competitive environment.
The only things that should be written as desktop software are applications that absolutely cannot be done in a desktop environment ( like games and P2P file sharing). But even then, doing it in Flash is better than requiring an actual download.
Another key factor is that with web based software you can do continuous releases, which is key in a competitive environment.
The only things that should be written as desktop software are applications that absolutely cannot be done in a desktop environment ( like games and P2P file sharing). But even then, doing it in Flash is better than requiring an actual download.