The entire article-- which amounts to roughly 6 pages-- is gaining traction on the Internet, but the focus seems to be Tagg Romney's pronunciation that his father "had no desire" to be president.
After a discussion of Romney's "private nature" and how he was more comfortable keeping his good deeds out of the spotlight, Tagg described his father's reluctance to run for office.
Via the Boston Globe:
More than being reticent, Romney was at first far from sold on a second presidential run. Haunted by his 2008 loss, he initially told his family he would not do it. While candidates often try to portray themselves as reluctant, Tagg insisted his father’s stance was genuine.
“He wanted to be president less than anyone I’ve met in my life. He had no desire to . . . run,” said Tagg, who worked with his mother, Ann, to persuade his father to seek the presidency. “If he could have found someone else to take his place . . . he would have been ecstatic to step aside. He is a very private person who loves his family deeply and wants to be with them, but he has deep faith in God and he loves his country, but he doesn’t love the attention.” [Emphasis added]
The Atlantic considers the statement in an article titled "Mitt's Son Said He Never Wanted to Be President Anyway":
So, yeah, that might explain why Mitt lost. Not wanting the job you need to publicly campaign for more than a year to get is step one in the "Not Getting Elected Guide for Dummies" book. Again, the rest of the mammoth piece, which you really should read, paints a larger picture of the struggle between Mitt's inner circle and his campaign advisors over whether they should humanize Mitt, which was ultimately their downfall. And, also, the Obama campaign had more staff and cooler tech stuff, like an app named Gordon, "after the person who punched Houdini in the stomach shortly before the magician died," and Narwhal, named after the Internet's favorite arctic whale.
Another of Mitt Romney's sons, Matt, told Conan O'Brien back in June that while the family wasn't eager to launch another national campaign, running in 2012 was "the right thing" to do for the country.