Haiti is a
country nation state loose conglomeration of people on the westernmost third of the island of Hispaniola. It is most well-known for its extreme poverty, and for being the first independent black republic in the world, and the site of the world's only successful slave revolution. It is also the home of Vodun.
As the French colony of Saint Domingue, Haiti was once the richest polity per capita on earth. That all changed when some hooligans got fed up with French colonialism and sent the Frogs packing. The fact that the slaves had managed to free themselves and create an independent nation out of a former colony scared the crap out of everyone in the Atlantic world, and the new state quickly became a pariah. Having promised large amounts of "reparations" to France for the loss of the slaves attendant with Haitian independence, Haiti got into a bit of a mess and a century later was occupied by the U.S., who were concerned about the growing German influence there. A former Marine became the de facto head of state.
A few decades later, Papa Doc and Baby Doc extended their reign of terror over the nation. It was during Baby Doc's reign that a populist overthrow happened, exiling the murderous family to France (how nice of the French, oui oui?).
This led Haiti into a period of
anarchy democracy led by America's favorite son, Jean-Bertrand Aristide, who was the target of a coup in the years following. The military took over, but under direct threat from the United States relinquished their power back to the anarchy democracy, whilst Jean-Bertrand was again elected. Once again a military coup ousted Jean (for good this time) and installed a merciless prick that unashamedly robbed the people blind.
A guy by the name of René was recently elected into the Presidential office. However, because Haitians kicked out all the farmers (they were smelly French people), Haiti has no economy, and, thus, no money...making the position of President a purely symbolic gesture. Just recently he has been seen on TV wondering what his country was going to do while he got the fuck out. The good news for Haitians is that their long-time rivals, the Dominicans, have buried the hatchet of the far-off Haitian invasion (that I forgot to mention) and are coming across the border to help their fallen neighbors.
A very few people control the vast majority of the wealth in Haiti, and they make no bones about spending it like drunken sailors. In their mansions overlooking the slums they gate themselves off and lavish themselves with exotic food and alcohol. All of them are in abject denial that there is any kind of problem with their lifestyles as the rest of the country destroys itself just trying to scrape together enough food to last another day.
Some time later
Another guy named Michel Martelly was elected into the presidency. Before that, his most notable accomplishment was starring in his own music video under the name "Sweet Micky". 
What makes everything so bad for the 2010 earthquake is the addition of all factors added together. A broke and ineffective central government means they have no rescue crews and no means of feeding, watering or sheltering any of the million-plus refugees. Their rocky past also means that the buildings were very poorly constructed, often using hay as filler in cement (especially in recent times after China quadrupled the price). Buildings were also built very close together and on the side of mudslide-prone hills that weren't properly prepared.
What's truly sad about the recent eartquake, is that if such a tragedy had never occurred, Haiti would still be in a slow, terrible earthquake of poverty and decay. For the sake of your fellow human beings, do what you can do to help!
Insult to injury
Recently, the Supreme Court of the Dominican Republic (where Haitians tend to emigrate to en masse) has declared people descended from Haitians to not be natural born citizens of the Dominican Republic, because hey, why not. This has led many, many people to be effectively stateless and citizenshipless, effectively not existing (although given how they are treated there, it probably didn't make much of a difference).
Needless to say, this has sparked much backlash and controversy both inside and outside of the Dominican Republic for obvious reasons. And also because the Dominican agriculture and construcion industries depend on extremely underpaid and overworked Haitian immigrants.