Here is one guy's analysis of why Obama won...
* He is a great orator.
* He was the beneficiary of the historic financial meltdown that occurred two months before the election and was seen as preferred over McCain because he articulated solutions better.
* Voters ignored Obamas past and significant radical associations and were enamoured by his rhetoric.
* He appealed to the younger (under 40) voters who, generally speaking, are not up on history and government, are accustomed to success without much hardship and need for personal responsibility, and are consumed by the entertainment industry which shares the same counterproductive values.
* He appealed to the many Americans who were unhappy with existing politics and policies even though the alternative remains nebulous and likely worse than what we have in the long run.
* He appealed to those who want "something for nothing"; promises of paying off mortgages, tax cuts, free health care, government assistance for this and that, bailouts and rescues. His economic policies were more tittilating than McCain's. It was a carnival midway-like come-on.
* He was considered Black (even though he is more caucasian and Arab), triggering a 95% turnout among blacks, despite the fact that many of these voters may not agree with his policies. It was race over policy. This is the converse of what one prominent black leader explained, one of the 5% who did not support Obama: "I didn't want to have race trump friendship", referring to his loyalty to Hillary.
* A gradually left-moving voter base.
And why McCain lost...
* Many of his policies were not that much different from Obamas' rheteoric despite his attempts to appear more conservative. For example, his desparate attempt to balance the ticket using Sarah Palin as a prop did not overcome his generally left leaning policies, especially his promotion of illegal immigration, and government bailouts. Ann Coulter amplifies this problem here.
* His age
* His mediocre communications skills