nothing. a country like spain is considered less of a safe bet so they pay more. a lot more. but here is the thing, most countries print their own currency. so even if they are irresponsible, they print more money and pay down debts, but that can lead to inflation, and a bit of that is better than defaulting all together. but now spain is part of the euro, they do not control their money anymore, and because investors are worried about the future of europe, they are charging spain higher and higher interest rates. at 7% they are going to default and if they default, they are out of the euro and then if they are out of the euro, the global economy will collapse. that is why you are hearing that the euro yields are important. the countries have trying to keep the yield down.