A quick overview of rumors about Obama which are widespread enough to merit treatment on Snopes... presented in reverse chronological order...
There are many listed on Snopes, including those that get recycled for every president, so I've chosen the ones that illustrate the relevant themes for this discussion -- the view that the Obamas are low-class people with socialist leanings who are essentially non-American (they don't understand America or are aligned with foreign interests) and only want to use their power to funnel income from hard-working whites to shiftless minorities.
Note that some of the rumors are false, but others are spin on actual events:
Obama
wears his flag pin upside-down to indicate his solidarity with Muslims and had a Marine relieved of duty for pointing it out.
Michelle Obama
dresses like a Hoochie-Mamma at an awards program.
Obama's
publisher says he was born in Kenya.
Obama makes
false charges against Navy SEALs, then tries to take credit for their work; Obama goes soft on terrorists at Gitmo, then tries to claim that information from the prisoners helped him get bin Ladin.
Michelle Obama
insults the flag.
Obama's lawyers
admit to birth certificate forgery.
Obama
doesn't know what Wisconsin's state flag looks like, assumes it's a union flag. (Rich irony in that one.)
Obama's Columbia ID states that he's a
foreign student.
Obama
throws a tantrum at a meeting with Congressional leaders.
Obama snubs American manufacturers and
orders a bus from a Canadian firm instead.
Obama
overpays his staff.
Obama has a
stolen Social Security number.
Obama supports
openly fraudulent payments to black farmers.
Michelle Obama behaves in a low-class manner around high-class Brits, and so
the Obamas are snubbed by William and Kate.
Obama
removes jewelry in observance of Ramadan.
Obama
admits he is foreign-born.
Obamas
live high on the hog in India at taxpayer expense.
Michelle
dresses in Mammy clothes at a foreign state dinner.
Kagan is nominated to SCOTUS for
helping Obama cover up his ineligibility for office.
Obama
lies about his father's military service.
Obamas
fly their dog around on his own jet at taxpayer expense.
Obama removes red-white-and-blue decor from office and replaces it with
Middle Eastern decor.
Obama delivers
unprecedented snub to fallen soldiers.
Obama
cancels National Day of Prayer.
Obama
hates the Boy Scouts.
Federal stimulus money goes to
save Michelle's brother's job.
Kenya claims to be
Obama's birthplace.
Obama
never attended Columbia.
Obama
desecrates Oval Office.
Obama
hates Christianity and the military and is sympathetic to terrorists.
Obamas
salute the flag with their left hands.
Obama
refuses to salute veterans.
Obama
called to court over problems with elegibility for office.
Obama
tries to claim that the Founders are socialist (or something).
AP
reveals that Obama is a Kenyan.
Obamas
pimp it up at a White House ball.
Obama was in the
Black Panthers.
Obamas
gorge themselves on lobster at taxpayer expense and rig an event in Montana to give a false impression of support for his policies.
Michelle has a
huge entourage paid for by tax dollars.
Obama has a
Kenyan birth certificate.
Russians
refuse to shake Obama's hand.
Obama had a
non-US passport.
Michelle
can't travel to Muslim countries because Obama is a Muslim.
Obama received
financial aid as a foreign student in the US.
Obama
interferes with SEAL rescue effort.
Obama
doesn't want to pay for veterans' health care.
Air Force One's
tail number is a racial slur.
Obama
funds Palestinian resettlement in the US.
Nostradamus predicts
America's downfall when a black president is elected.
Obama
snubs police.
Obama's association with domestic terrorists makes him
ineligible for a security clearance.
Obama
admits to being a Muslim.
Michelle
pigs out on room service. (Why is it always lobster?)
Obama
won't speak the name of Israel.
Obama reads
books by Muslims who oppose US power.
Obama is
buddies with Bill Ayers.
Obama wants to
force banks to make bad loans to poor people.
Obama's
finances are shady.
Obama wants to
forcibly redistribute wealth.
Obama
replaces US flag with his logo.
Obama
snubs soldiers in Afghanistan.
Obama has a
forged birth certificate.
Obama wants to
tax working people heavily to pay for socialized medicine.
Obama
campaign paid for by foreigners.
Obama
not a natural-born citizen.
Obama is an
anti-white racist.
Obama
lies about his background, credentials, religion, voting record, etc.
Obama
involved in Kenyan politics.
Obama wants to
replace National Anthem with Coke jingle.
Obama wants to
take away gun rights, and raise taxes on the weathy to fund socialist programs.
Obama's
family are a bunch of low-lifes.
Obama wants to
fundamentally change America.
Obama
lies about his connection to the civil rights movement.
Obama campaign
funded by Hugo Chavez.
Obama
refuses to salute flag.
Obama is a
radical Muslim.
So the question is, why is it that these rumors in particular are the ones to gain traction?
The pattern is pretty clear.
The message is the one that folks who are most likely to oppose Obama are most likely to believe -- he is not like us, he is not one of us.
* The Obamas are low-class people with low-life families who lie about their credentials and don't deserve to be where they are.
* Obama is a foreigner, and his rise to power was supported by foreigners.
* The Obamas don't know how to dress or behave in high-class company.
* The Obamas are living it up on the public dime.
* Obama wants to funnel money away from wealthy and working people and give it to other shiftless low-lifes.
* Obama does not believe in our religion and doesn't understand our institutions or values.
* Obama is in cahoots with anti-American interests, especially radical Muslims.
All of this, of course, plays into racial stereotypes and racial fears.
People believe this because they are already predisposed to believe such things about blacks, Democrats (especially Chicago Democrats), and people who have spent time outside the US (especially if they were partially raised overseas).
The days of publicly railing against the uppity Negroes are over (except in my state, where my own representative called the Obamas "uppity" and stood by it), but it is still possible to play into that stereotype without coming out and saying it, and that's where the propaganda has gone.
It allows Obama's opponents to feed on those unspoken stereotypes without coming out and actually naming them themselves, which gives them a "Who, me?" excuse if charges of racism are raised. (ETA: See also, for example,
Gingrich's comments on Obama's misunderstanding of the UK because of his Kenyan mindset.)
But it's difficult to look at that pattern of rumors and not see what's going on.