I had been hearing about this and was wondering what the heck it was.
Well, here is what I found out from my limited research.
Basically, it is a downgrader.
Microsoft is actually giving you something to downgrade their product. This tool is meant to be used to backlevel machines that have upgraded their versions of Internet Explorer but are not at Windows 2000 level yet.
Personally, I do not see the point since most upgrades are just FDisks anyway....
Anyway, this will bring IE back a few levels since 5.01 gets installed by default with Windows 2000.
This might be a handy tool to keep around for any possible problems with IE in the future. It also might be nice to be able to back out of the upgrades in a hurry.
Here is an MSFT article regarding the topic:
Let me know if you have any luck (or unluck...) using this tool.