An anonymous reader writes: A bunch of Facebook users received mysterious messages yesterday congratulating them on 46 years of being friends with somebody on Facebook. An astute observer may note that Facebook hasn't been around for 46 years. An even more astute observer might note that 46 years ago yesterday would be 12/31/1969 — easily recognizable as value '0' in the Unix Epoch with a time zone adjustment. A Microsoft engineer posits that the messages were sent because of how Facebook implemented its congratulatory messages. Many people were Facebook friends when the feature was rolled out, and instead of finding or estimating the date they became friends, Facebook simply set that database value to '0'. When the script fired to send those messages, it grabbed that value expecting a time, and interpreted the 0 accordingly. "The developer who wrote the "friends with since" memories algorithm should have added a case WHERE friendsWithSinceDate != '0' or something along those lines."