Let's say that 100-150 years from now we've established a handful of colonies on Mars. Some of them are research stations and some of them are legitimate towns/cities or corporate operations. Point is, they're only the size of a small town at their largest and there are less than a few dozen of them. Mars DOES NOT have a unified government or even very many permanent residents, and all the colonies are directly affiliated with the governments and organizations on Earth that are sponsoring them. Although the colonies are self-sufficient in as far as food, water, oxygen and building materials, they rely on Earth for continued funding and commodities. Mars at this point is largely a mecca for scientific research (possibly of past or present alien life) and also serves as a waystation for belt mining. It is NOT an economic power, although shipping people and materials to and from Mars isn't quite as prohibitively expensive as it is today due to either antimatter or cheap fusion power (there is no interstellar travel though).
What implications would this have for societies down on Earth? Would people volunteer to live on Mars as guinea pigs? Would Mars be a source of cheap housing for the homeless or would relieving poverty in this way be too expensive to be practical? Would it be an attractive tourist destination or a source for any unique commodities besides belt-mined ore and water? How would human society at large be affected by Mars colonies both at the time of their inception and after they've existed for a hundred years?