I would agree that on land makes a lot of sense in terms of living space, but in terms of trade and all of the other factors which have traditionally driven hum

I would agree that on land makes a lot of sense in terms of living space, but in terms of trade and all of the other factors which have traditionally driven humans to the coasts, not so much. By contrast Mars offers nothing that isn't more readily obtained from asteroids, and still offers a gravity well to be stuck in. If you want zero G, vacuum industries, that kind of thing... moons or large asteroids make much more sense than Mars. A terraformed Mars makes sense, but it's not exactly impending. If you just think about it terms of colonies on Earth, colonies existed because they had something to offer the "mainland". Sugar, rum, slaves, spices... something. Colonies without that benefit didn't stay colonies for long, and what's the point of creating... I don't know... SpaceHaiti2000?