We don't market to any group per se. I think the different countries that end up visiting here do so because where I am is a pretty big 'touristy' area and has gotten a lot of press in guidebooks, magazines, online, etc. Because of location- 'NEW' England, our demographic is European. Altho, I do have quite a lot of pins in the map from Brazil.
How we get them is another mystery. MOST of them say they found me in guidebooks. So, there's a place to start. If you can get into a guidebook, that will also be online. Others just decide to come here, want the B&B experience and find us doing a search on Google.
I do target European and Asian visitors. I have my availability on sites they use, such as booking.com and hostelworld.com. Granted my place is more for the budget minded traveler, so the latter works. Also I look for European sites to join.
If you want to target English visitors and european visitors I would try Laterooms and Booking.com they operate a number of different web sites but you only need to update your avaliability on one. They work on a commission basis so you only pay for what you get
I am curious about the South Americans part of the question, I would like to hear more about this when you have the chance, we have never had any South Americans here. We do have Europeans and visitors from the UK and other countries and continents from time to time.