Desktop software has the benefit of perceived privacy and being easily scalable, as you pay for a filehost and installations are done on each user's computer.

Desktop software has the benefit of perceived privacy and being easily scalable, as you pay for a filehost and installations are done on each user's computer. However, the problem with this is that once any user sees a bug, screws up their registry, deletes a file, upgrades or installs a Firewall that starts blocking ports or an Anti-Virus program that's over sensitive or slows your application down, installs a new or different Service Pack, then you will receive questions that you now have to answer and debug that have nothing to do with your program. Then you have to create and release an update, making the customer wait, instead of being able to change things on the fly, as is possible with many web app frameworks.