Highly unlikely that there is anything sophisticated here. It would be too many computing cycles thrown at something with very small RoI. Most likely some straightforward text, date, and location matching. Many of the previous commenters are assuming you need sophisticated pattern sifting to get any good insights. Not true. Large numbers of facebook users are including this data voluntarily or with their unexpurgated photos. Going after the sliver who don't is just not a worthy investment -- yet.