It's subtle, but important. AP, in reporting about the Internet effort to slime Obama by falsely claiming that he's Muslim, didn't bother actually SAYING that the rumors were false, that the campaign was clearly misinformation. Note how AP refers to the false rumors as simply "concerns":
The Illinois senator also sought to ease lingering Internet-fed concerns about his religion, in particular whether he was a closet Muslim.
"I am a devout Christian. I have been a member of the same church for 20 years. I pray to Jesus every night," he declared at an earlier appearance in the rural southern Ohio town of Nelsonville. He said he wanted to halt "confusion that has been deliberately perpetrated."
Now, AP knows this is untrue. They know that the allegations aren't just lingering Internet-fed concerns about his religion - they're a bigoted online campaign intended to slur, to Swift Boat Obama, with something everyone knows is false, and racist to boot. These aren't "concerns." Who has concerns about Obama's religion? It's all smoke and mirrors, and AP knows it. And while AP quotes Obama as saying it isn't true, that's not the same thing as AP acknowledging in its own editorial voice that these rumors aren't true, that there aren't lingering "concerns" about Obama's religion at all. The story should have called them "false rumors," and not "Internet-fed concerns." AP should have said they independently confirmed that Obama has always been a Christian, that he has in fact attended that church for twenty years. But they didn't, even though they know that this "Internet-fed rumor" is part of a huge effort to defame Obama.
It's a slight nuance, but an important one. The media was happy to aid and abet the Swift Boating of John Kerry in 2004 by reporting on the he-said-she-said of the Swift Boat allegations as if they were news, as if they were real (when everyone in the media knew the allegations were trumped up). Rather than writing process stories about how ludicrous the attacks were, and how interesting it was that the Republicans were willing to go this negative, the media kept asking John Kerry if he really did steal his purple heart. We're not going to let if happen again. When you write about Obama being Swift Boated, say it. Don't report it as a he-said-she-said, as something that might just be true, so let's get Obama's side and present both. Call it what it is - a lie. False. Untrue. Don't just quote someone claiming it's not true, say it's untrue. Otherwise, you're simply feeding the lie.