Right now I track installs of a particular piece of software through the use of a cookie. (This is all windows currently.) Since the download comes from my site through a link I can give custom links to affiliates to figure out who to credit the download with. I also assign a unique id of sorts to the computer to track it. These get popped into the registry at some point in the future for persistence.
Now, there are more ways to spread the software rather than just through a download link -- I want the ability to just hand someone an .exe and figure out who gave them that. I could have a .ini file or something to hold the tracking code but that means I have to create an installer for each affiliate -- I'm not completely against this idea but I don't like it either.
Any easier ways? I know this is a common use case -- what do people do?