Only if there is anything to trade which I think is rather unlikely because of differences and distance.
If they have money...
Once upon a time, there was this road, and it took about a year to go from one end to the other with your caravan. And people were still willing to leave behind their friends, their families, to travel this road. This year to travel this road, it could even be longer, depending on whether or not you ran into bandits who would kill and rob you, or into hostile kingdoms that had radically different cultures than anything you could even have conceived.
Why did they travel this road? Why, simply to get the byproduct of some insect catching dinner. Silk was a pretty big deal back then. Trade of anything we could find on earth would be prohibitively expensive, but that doesn't mean we wouldn't send caravans to get those luxury goods that just simply don't exist on Earth, and you can't tell me that with an entire planet that's just as full of life as Earth is that we wouldn't find something. And money? That's a fairly modern concept, humanity did quite well (and still does, in many areas) simply bartering for what they want.
I agree with the sentiment that we wouldn't have been chatting it up with 'martians' back in the twenties, but we wouldn't have exactly been ignorant as to their presence. The debate about the canals of Mars was pretty fresh in the early 1900s, and more powerful telescopes were being made at around the same time radio was getting into the scene. We would have probably seen their equivalent of London before we heard their first radio broadcasts, or at least before we were able to identify their radio broadcasts as something indicating intelligent life.
The thing I wonder, primarily, is what effect would the discovery that an alien species was able to listen in to our radio (and later television) broadcasts have on our society. Would we have even commercialized television for the masses, or would it have been kept as some sort of military-only technology? Would the knowledge of the likelihood of alien life nearby changed WWII? If not, would the rampant paranoia after the war brought around military preparations for a potential invasion, or would we have overcome that and learned to communicate? Would we be watching Martian Box Office's version of Game of Thrones on the Interstellar TV Network? Would Sean Bean find a market where he could play a character that didn't die?
People always like to cite the psychological issues of a manned mission to Mars as this giant, game ending barrier. Yes, it's a problem, but then again, so was a three month journey on a wooden boat in 1492 to a land that no one was even sure existed. They couldn't even supply themselves well enough to prevent simple diseases from ravaging their health. We can do much better.
The human spirit is pretty strong, and if there's sufficient motivation, we'll find a way to put up with all kinds of hardships to get what we want, and I'm pretty sure there would be a lot of people interested in traveling to Mars to learn, trade, and explore. Personally, I'd be interested in traveling to Mars now, even knowing it's a one way trip, and so would many other people. Imagine if there was a society that could keep us in breathable atmosphere, catch supply packets sent over in advance to feed us, and top up the gas tanks so we could come back?
