I use "address book" in Palm
I am a pretty lo-tech person. I use Palm Handheld and desk top version. I try to put everyone I need to remember stuff about "on the fly" or in perpetuity in my Palm address book. I use the address field and the note section. I add to the notes from the "top down" beginning a sentence with the date. Palm is pretty searchable. Or, if you don't exceed 15 categories, you can put people in categories and then search through the category. I have an 83 year old friend who has binder with A to Z tabs and a page for every person whom she has ever meet and retained a relationship with, business or perosnal, so she has all the info like when she last them the person, who has a grandchild, and she also runs a business and has the same.