Here's a good breakdown of that 47% number Romney used, in case you just want to have it handy, or if you're not in the US and are still actually curious who exactly he was talking about (It's too messy to just copy/paste the whole article, so I'll try to do the basic pertinent facts):
http://www.washingto...t-those-people/
53.6 percent of households pay the federal income tax.
28.3 percent of households pay no federal income tax, but they
do pay the payroll taxes for Social Security and Medicare. That means they don’t need Mitt Romney to convince them to “take personal responsibility and care for their lives.” They already have jobs. Most of the households in this group don’t pay any federal income tax because they qualify for enough deductions that their income tax liability has shrunk to zero.
10.3 percent of households pay no federal income tax because they’re retired and elderly. Many retirees aren’t taxed on their Social Security benefits, which they earned by paying into the system over many years.
That leaves
6.9 percent of households which are non-elderly and have incomes less than $20,000 per year and aren’t paying the payroll tax. These poorer households pay neither income taxes nor payroll taxes.
Meanwhile, just as a reminder, the vast majority of Americans still pay state and local taxes — in fact, these taxes tend to be more regressive. When you add up
all the different types of taxes, most income groups in the United States tend to pay an amount that’s roughly commensurate with their share of the national income.