What a great idea!

Mouser is right about just keeping your own log if it's just your machine. But I couldn't help thinking of a bigger picture.
An uninstall log would be extremely useful for forensic and postmortem support analysis functions. I can't tell you the number of times I've had to troubleshoot a system, where the problem was caused by a piece of software that was no longer on the machine. If I knew somebody had installed and removed something in my personal 'rogues gallery' of ill-behaved applications, I'd be way ahead of the game. So if there was a way to keep an automatic audit trail of all installs and uninstalls, I'd be more grateful than words could tell.
Thought: Maybe you could suggest it to somebody the VS Revo Group if you don't want to develop the idea yourself? They make the excellent freeware Revo Uninstaller. They're usually quite receptive to suggestions for product improvements.
http://www.revouninstaller.com/contacts.html
EDIT: If you want to keep a handy tech journal on your computer, check out the freebie Advanced Diary:
Link:
http://advanced-diary.uptodown.com/en/It's a great little app. I have a copy on each machine I own for keeping notes, registration codes, etc. You could also use any one of the free tree-type note organizers if you don't like the daybook metaphor.