Overrall effect of changing system date on OSX

"The only issue I have had with the Date Time on OSX so far is when it goes back in time. If your using MobileMe it can affect the Sync times. Otherwise it should have little or no impact apart from affecting any time based applications like calendar and any time display, which is items I am sure you are more then willing to deal with :)

I would also imagine it could cause some confusion for Time Machine if you are using it.

Apart from the above, no their shouldn't be anything directly affected by it."