Why Are There Undecided Voters Still?

At the debate tonight, they have a room of undecided voters.  My question is why they are undecided?
You have 2 candidates who are almost completely opposite of each other.  There have been numerous news stories written about the campaigns, numerous commercials and many people thye can talk to.
So, why are they undecided less than a month before the election?
Could it be they are ignorant and don't know the facts?
They don't watch or read the news?
They don't have friends?
Or, more likely, are they are lying that they are undecided so they get a chance to be on TV in front of 60,000,000 people and they may have a chance to swing the election in their candidates favor?

Update: Michelle Malkin has information the last time CNN had a town hall debate: 
At CNN’s Democratic debate in Las Vegas two weeks back, moderator Wolf Blitzer introduced several citizen questioners as “ordinary people, undecided voters.” But they later turned out to include a former Arkansas Democratic director of political affairs, the president of the Islamic Society of Nevada and a far left anti-war activist who’d been quoted in newspapers lambasting Harry Reid for his failure to pull out of Iraq.
Yet CNN failed to disclose those affiliations and activism during the broadcast.
Behold – the phony political foliage bloomed again at Wednesday night’s much hyped CNN/YouTube GOP debate.
Oh, CNN did make careful note that Grover Norquist (who asked about his anti-tax pledge) is a Republican activist with Americans for Tax Reform. But somehow the network’s layers and layers of fact-checkers missed several easily identified Democratic activists posing as ordinary, undecided citizens.
The tallest plant was a retired gay vet, one “Brig. Gen. Keith Kerr,” who questioned – or rather, lectured – the candidates on video and in person about the “Don’t Ask, Don’t Tell” policy that bans open gays from the military.
Funny. “Don’t Ask, Don’t Tell” was exactly the policy CNN adopted in not telling viewers that Kerr is a member of Lesbian-Gay-Bisexual- Transgender Americans for Hillary.  http://michellemalkin.com/2007/11/30/cnns-dont-ask-dont-tell-policy/