By the end of my semester in Milan, I will have visited 18 different cities in 10 different countries. It has been an insane amount of travel, but it is only the extreme case of a larger, much more pervasive trend in my life – in our lives.

Even in my normal life, I am constantly on the move. Home is Chicago. School is Los Angeles. Summers are Shanghai, New York, San Francisco. Week-long trips to Nicaragua, Panama, and so on. And I’m not the only one – my friends are equally mobile. The 200 students who made up my high school class have scattered across the country, and are now floating around the world.

This creates two simple desires:

1. When I get wherever I’m going, I want to know if any of my friends are there.
2. If my friends have been where I’m going, I want to know what they thought.

Of course, I’m not the first person to recognize these desires. There have been a deluge of startups dedicated to solving these problems. Arrived, a startup that I have watched excitedly for months, just launched and is tackling the first desire. During my travels, I have tried Trippy with some success, though it seems to require too much effort from the recommender when addressing the second desire. The latest I’ve seen, TripBirds, is set to launch soon and will be joining me at LeWeb.

But these startups are missing something very powerful, and that is my favorite travel app of all: TripIt.

Using TripIt is a wonderfully simple process:

1. I book a travel arrangement, like a flight, train ride, or hotel stay, and then forward the confirmation email to TripIt.
2. TripIt translates the email into an event, which is automatically imported into my iCal (or other calendar), including confirmation numbers, seat numbers, etc.
3. When I travel, I have the information at my fingertips exactly when I need it.

TripIt is the most powerful travel application that I’ve seen, and it isn’t just because it has made my travel so much more convenient. It’s because TripIt has data, on the city/region level, of where I am and where I’m going.

Of course, these days Facebook has a lot of the same information, and it is Facebook that drives Arrived, Trippy, and TripBirds. Facebook, with a user base exceeding 550mm users, is obviously a gargantuan source of data as well. But TripIt distinguishes itself by automatically collecting predictive data on where their users will be. Plus, its information is more complete; in my case, TripIt knows a lot about every time I make a major move.

In other words, TripIt has data on the future. What a great basis for making plans! Sure, it’s not as big as Facebook, but it represents an extremely valuable additional layer of data.

I want to spend more time learning about TripIt and the data available through its open API. I’ve contacted TripBirds already about the possibility of adding TripIt (currently, they have Facebook, Foursquare, Instagram, and Gowalla), but more broadly, if anyone is building tools for travelers, take a moment to think about TripIt – and get in touch with me, because I would love to help you think through it.