[zipdog]

I tried that experiment, and the first couple of years it was about 50/50, but most recently almost everyone who posted did so on the FB birthday date. I think theyv'e come to rely on the Facebook reminders.

It was also interesting to see the cognitive dissonance from some posts: "I'm pretty sure it was your birthday next week, but Facebook says its this week, so Happy Birthday".

[freehunter]

Of my friends who are friends but not best friends, I only know one of their birthdays. I only know that because her Xbox Live gamertag has her birth month and day in it (and she was born one year and one month before me, kind of interesting I guess).

Birthdays are a thing that are hard to remember. People used to mark them down on a calendar or just wait for the person to remind them. Both of those functions have been replaced with Facebook now.