These days it's hardly surprising to have a stranger knocking on your door to tell you how presidential candidate Barack Obama or John McCain is going to change the country and how important it is for you to vote, dpa reported.
In the current race to the White House, thousands of volunteers have fanned out across the country, sacrificing their weekends and devoting their spare time toward such door-to-door canvassing.
Two young professionals from New York, who asked not to be named, have travelled 160 kilometres to Philadelphia over several weekends to volunteer for Democrat Obama's campaign.
Philadelphia is the biggest city in Pennsylvania, which has emerged as one of the key battleground states in this election. Both candidates have focused a lot of attention here, as they have in other important states such as Ohio, Florida, New Mexico, Nevada and Colorado.
According to figures released by Obama's campaign in Pennsylvania, their volunteers have so far knocked on 2 million doors and made 3.8 million phonecalls, as well as organized 6,000 events since June. The exact number of volunteers could not be determined because it changes on a daily basis.
The McCain campaign's Pennsylvania office said they could not give figures, but noted that some days "hundreds" of people turned up to make calls.
On one recent Saturday morning, the two professionals from New York travelled to northeastern Philadelphia where Obama was speaking at a rally. They arrived at Obama's campaign headquarters, where scores of young volunteers were receiving instructions on how to get out the vote.
The two were asked to call on undecided voters, so they got into a car with a long list of addresses of potential voters. They started in a working class, Roman Catholic neighbourhood.
"Last weekend I knocked on some one hundred doors. It was tough," one of them said.
It isn't easy to find people home on a Saturday. Those who are in often don't want to open the door - they get a leaflet about Obama in their mailbox.
Some do heed the doorbell. At one grey apartment block, a lady looks out of her window to see who the caller is.
"We want to know if you're going to vote," the volunteer says.
"Yes, yes, for Obama," the woman replies as she closes her window.
The answers are usually short and there are no questions asked about what each of the candidates actually intends to do. The longest conversation the two volunteers had was with a woman in her 40s, who was relaxing outside her house with a cup of coffee.
"I would have voted for Hillary Clinton, but now I don't know. The truth is I'm not really involved in politics," she says.
The volunteer tries to convince her to vote for Obama, who is a Democrat like Clinton.
"Oh, is Hillary a Democrat?," the woman asks.
Others do not need to talk, or even to open the door. One voter who is listed as undecided has clearly changed his status - he has signs with the names of McCain and his running mate Sarah Palin on his front yard and fence. The volunteers say there is no need to ring that doorbell.