So, you were asleep for the entire 2008 campaign, then?
The Obama Campaign denied this at the time. No, they had not "air lifted" operatives to Alaska. They already had plenty of them in the state!
Dirt proffered by the DNC and the Obama campaign, or developed by the news media and pushed by the Obama campaign (I think we can all agree that there is no separation between the Obama campaign and the mainstream media. Certainly there wasn't one in 2008) include the charge that Palin belonged to a secessionist group and had radical anti-American views, that Trig was not her child, that she had strange religious views and disrespected Catholics, that she offered to have sex with a beauty pageant judge (Oh, wait, that was a spoof. It's so hard to tell mainstream media reports from a spoof.)
Sampling from among hundreds and hundreds of such stories:
Pastor: GOP may be downplaying Palin's religious beliefs - CNN.com
In Palin’s Life and Politics, Goal to Follow God’s Will
The Trig Palin Hoax Theory All Hinges On One Telling Photo - Business Insider
Palin's secession flirtation - Los Angeles Times
Palin’s pastor (and witches) problem - Salon.com
There's no question that all of this nonsense had a profound effect on the public perception of the McCain-Palin ticket.
If Obama hasn't dug any dirt on Romney so far I doubt it's from a lack of trying. They tried the Mormonism = Cult angle, if you recall, but it backfired on them. They also tried the Romney is cruel to dogs meme until it came out that Obama used to eat dogs.