Despite the fact that as a presidential candidate Barack Obama ran several national ad buys that brought campaign advertising to California, Utah, and a number of other states that hadn't experienced the excitement/overkill of campaign season in quite a while, battleground states still dominated ad purchases. According to Fair Vote:
Percent of all presidential campaign related television ads that took place in [Ohio, Florida, Pennsylvani and Vriginia] from September 24 to November 4 54.5%
The campaign was consolidated in other ways as well:
Percent of all 300 campaign events by major party presidential candidates between September 5 and November 4, 2008 that took place in the states of Ohio, Florida, Pennsylvania and Virginia 57%
Number of states where 99% of all campaign visits and 99% of all campaign spending took place: 16
And the effect of this? Just over 10 percent in voter turnout.
Voter turnout in the 15 states with the most campaign activity: 69%. Voter turnout in the remaining states: 56%