I'm an ENFP whose mnemonic genius pretty much extends to little details about people like their birthdays, their favorite colors, etc. but I'm also pretty good at remembering dates of certain events, even if the events themselves are blurry. I'm very much given to remembering what people tell me and what I hear. For example, about five years ago in elementary school my friend (who I never talk to now) told me her birthday was January 4th; a few weeks ago in French class one of my newer friends asked another when that friend's birthday was. I was able to tell them what her birthday was, but not why she told me or whether we were talking in class.