When you are acquainted with a lot of people who move around a lot, it is always a good idea when arriving in a new place to see which of your friends still live or have moved from the place you are visiting. This is easily done with something like facebook, where you can search your friends by city. Sure, it leaves out people who aren’t on facebook, who don’t put in their current city, or who live just outside the city (yet still in the same general area), but it will give you a general list of who is there. For people like me with a lot of acquaintances and a terrible memory, this is a great tool. And sometimes one is surprised to find that friends from one city have moved into the city one is visiting. Such was the case with my friend Guillermo, who I met in Buenas Aires a few years ago, and have seen at various times in New York where I live and in Barcelona, where he lived until he moved to San Francisco (temporarily) about a month ago. We just had a lovely coffee at Fourbarrel and then lunch at Serpentine (another great SF restaurant). Guillermo is a bit of a nomad like me, and we have lived in a lot of the same places. He lived in Mexico City for a while and spent time in Mumbai, and we even realized we know a person in common from there this morning. All these intersections and commonalities fascinate me, it is so striking how small the world can be.