The first time in history were a wittness of a USA presedantial campaign. Obama spaned all over the world through the medium of internet. The people who lives in many countries sustain him. One of the most important reason of this interest is his mixed blood.
Internet was used by Barack Obama during the whole presidental campaign effectivelly. He also used forums, MySpace and Facebook.
For detailed information:http://en.wikipedia.org/wiki/Barack_Obama_presidential_campaign,_2008