some documents, like ms office documents, have a strange effect on the program that tries to launch them, and essentially lock up the process for a few seconds even if executes with "shellexecute", so essentially when farr finds a program that it thinks could do this to it, it instead launches quickdocklauncher.exe with commandline parameters that instruct it what document to launch, so that farr can resume working right away.
bottom line, not very useful to you outside of farr use.