666, the mark of the Beast (Anti-Christ) in Revelation is described as the name of a man and is the product of Hebrew Numerology. So lets take a look at what it actually is:
נ = 50
ר = 200
ו = 6
נ = 50
ק = 100
ם=60
ר = 200
This spells "nrwn qsr", Hebrew for "Neron Kesar" which, when translated, means Nero Caesar. The description of the Beast, among other things, points directly to Nero and the Roman Empire but, as if that isn't enough, we also have translation on our side. Greek manuscripts of Revelation have the number 616 instead of 666. Why? Because the Latin form of Nero Caesar adds up to 616. This proves that even the ancients understood the mark of the Beast to be a reference to Nero Caesar.
Lets also take a look at just one of those "other things":
In Revelation chapter 17 we read of a beast with seven heads and a woman sitting upon it. An angel deciphers it's meaning in verses 9-18. The angel says that the seven heads represent seven hills and seven kings (also that five have fallen, one still reigns, and one is yet to come but reigns for only a short time) and the woman represents a great city which rules over all kingdoms. So what does this mean?
Seven Hills = The seven hills of Rome. (Cermalus, Cispius, Fagutal, Oppius, Palatium, Sucusa and Velia)
Five Fallen Kings = The predecessors of Nero. (Julius, Augustus, Tiberius, Caligula, and Claudius)
One King That Is = The current Caesar when John was writing Revelation. (Nero)
One King That Will Be But Reigns For Only A Short Time = Nero's successor. (Galba, who reigned for only 7 months and 7 days)
The Woman That Is A City = The city of Rome itself.
And why shouldn't it be Nero and the Roman Empire? Afterall, Jesus did tell the apostles that what people describe as "the end times" would come during their generation. (See Matthew chapter 24, Mark chapter 13, and Luke Chapter 21). Seems to me that these prophecies aren't about the end of the world and the literal return of Christ at all but the end of the persecution of Christians and the establishment of Christianity as a major world religion.
The idea that Obama is the Anti-Christ described in Revelation is laughable and only circulated by those who hate him. Don't believe them.
That is the only reason I can think of. A lot of people don't understand that just because the Mayan Long Count Calendar ends at 2012 doesn't mean that the Mayan's believe that the world would end in 2012. It represented the end of a cycle of creation and the beginning of a new one and there are Mayan Calendars which go all the way into the 4000's.