What were the economic crisis causes?

As we all know in this times we're all suffering an economic crisis. I read an article of what caused the economic crisis and it was really interesnting because it says that the cause of the crisis can be sum up in one word that is GREED. And this happened when everything was ok the houses were being sold at really high prices, prices were going up like every month. and the lenders borrowed money more easily, and these was really good for them because they gain more money because of interet or if not they cold keep the thing they bought like the house and sell it to a higher price. But all this shocked when many of their costumers couldn't afford their payments and all this become a problem. This is article is really interesting because it explain really well how the economic crisis emerged.
if you want to know more about this here is the link: http://www.moolanomy.com/866/what-caused-the-financial-crisis-of-2008/