I find the coverage a bit strange. In the UK, the exit polls are used as a predictor, but the results are announced only once the count for that area is completed, so you have a definite outcome. Then an overall result is given only when it is clear who has the majority.
But in the States, they show the count as it happens. So they give the percentage of the vote counted and the number of votes and percentage of votes for each candidate. Then depending on how the vote is going, and various other factors like exit polls, interviews, voting history etc, CNN gradually makes projections as to who will win each state.
Some, like Florida this year weren't being projected even with 91% of the vote in, as it was considered too close to call, even though they were estimating that Obama would take it. Conversely, some states were being projected even though only 50% of the vote had been counted, or like Ohio, which had only about 150,000 votes, or one percent difference at about 80% counted. By about half past midnight (East Coast and Cuba time), CNN had projected that Obama would win and were looking to Romney to concede.
So even though a lot of votes had not yet been counted, and there is technically plenty of scope for a large glut of votes for the back runner to alter that state's result, people take the projection as a final outcome and celebrate -or not - accordingly. I am sure that the method must be tried and tested, and that it normally proves correct, but it still seems pretty strange to me.
But anyway, after some of the comments that Romney and his allies have come out with, I personally am very glad to see Obama back in. Romney did concede at about ten to one. Around an hour later, Obama gave his speech which was reasonably good, but given that the split of actual votes was so close to being 50:50 it was necessarily conciliatory too.
But I would like to leave you with my favourite moment of the coverage, which actually came just after midnight at the start of the day. A place called Dixville Notch only has ten voters and they all came out so that they could vote as soon as the polls opened, and be the first to announce their result. It didn't take long. They have three registered republicans, two registered democrats and five independents, and generally vote republican but last year voted for Obama. This time around, a majority of six voted for a Republican congress, a majority of seven voted for a Republican governor, but five each voted Obama (Democrat) and Romney (Republican), the first ever tie in Dixville Notch.