time is a weird thing on the computer, in real life time is already weird since there is a future and a history. but in reality there only is a now.
well on the computer it will get a lot weirder. on a computer time is not synchonious, especially with networked computers and time synchronization the time can go from a moment in time to a moment in time before. so a computer can travel back in time! then later on it can travel forward in time again. especially with software that records history or the moment some things were recorded this can have huge implications!
for instance: imagine a log mechanism that records when an action is done, then the user can look in the log to read back if they did something or not or if the computer recorded the action and performed it correct. well if you display the log sorted on the date/time you recorded the action at, then it might be that (say if a clock chip failed) the last entries are sorted all the way to the beginning of the log. now the user checks if the action they did is performed correct and they see nothing is done at all (because it is not at the end of the log but at the beginning).
well, this seems a small problem but i can tell you that at my company (mobile satellite phone business) we could cause a lot of trouble this way. a user could accidentally added too much credit to their satallite phone with all the trouble that comes with that, angry customer, phones going over their usage limits, billing diputes, etc.
the moral of the story, never forget that time in not synchronious in a computer and that dates and times are never to be trusted fully!