Even when we get the names down, the personal data (did they grow up in New Hampshire or Maine?) can be elusive. Linda commented on my post about connecting with people in business asking how I keep track of all the tidbits.
My answer is to pay attention to a very few people. Which is not really an answer, but an explanation that I do not deal with so many people just yet that I have to have a real system. If I do, I will start posting such data in our project tracking tool, within our company forum. That way anyone talking with the client (not that anyone else should be) will know that so-and-so has a newborn.
The problem with this is, maybe the information I learn about should be kept, not private, but not public. Jory calls it Stalk Marketing when someone you don’t know finds out a lot about you in order to sell you stuff.
Key point, know who you are dealing with and how they feel about their personal information. And err on the safe side.