My memories are tricky - especially short term memories - someone tells me something, and it goes into my brain and parks itself into a hole in the Swiss cheese. It's THERE, I just can't access it unless the hole opens up.
And, as anyone who reads this and who has epilepsy knows - the normal mind tricks for remembering things, from writing it down on paper (I will lose it 100% of the time) to high tech stuff like entering it on my Xoom or Galaxy phone - it is only helpful if I remember that I even put it there, which means I have to remember several things:
1. what format I "wrote" it down in,
2. where the device, paper, etc., is,
3. what information I'm looking for,
4. do I trust you to know that you actually gave me the information,
5. do I actually remember talking to you or interacting with you in the first place.
6. And in extreme cases, do I even know you or remember meeting you in the first place?
It's next to impossible to remember something you told me, if I don't even remember talking to you.