Rural people often rich, urban people often poor shocker
It costs more to live in the countryside (have you seen the price of petrol?), therefore it should come as no surprise that a higher percentage of rural people have broadband, because there is a higher percentage of rich people.
What this totally fails to address is rural poverty. There are more people classified as below the poverty line in rural areas in the UK than there are in any one major city. Rural poor outnumber London poor. Rural poor outnumber Manchester poor.
This is a problem for rural connectivity because cheap broadband is not available and there is little competition (there is essentially one monopoly - BT ADSL wholesale - who are resold in a number of guises, but never below the BT ADSL wholesale price). There are no cable providers, no local loop unbundling and no 3G coverage, so whilst a poor family in the city can afford 5-quid-a-month LLU broadband, this simply isn't available to poor families in the countryside.
Townies often ask "why don't they just move?" but the problem is that most of those who can, already have. The remainders are so poor, they can't. Rural poor live in run-down, low-demand housing, notably council houses which they may have bought at a discount, but their inability to refurbish their house means the value has not kept pace with the market. They can't get a job, or a better job, because they typically don't have cars or, if they do, can't afford to run them more than a couple of trips per week. They can't use public transport because buses and trains rely on large groups of people at point A all wanting to go to point B, and in rural areas, not only are the no large groups of people, but there is no common agreement on what points A and B are (typically there will be half a dozen nearby small towns, and no large city; the buses, if they exist at all, won't serve all the towns from all the villages).
The answer? Well, for connectivity BT WBMC looks promising, and 3G coverage is always expanding. And rural poverty? Ironically, the answer may well lie in telecommuting.
The real measure should be the percentage of poor connected, not the percentage of the populations as a whole.