Frontman Caleb Followill explained the song's meaning to The Sun: "While you'd expect the track 'Family Tree' to be about family, it's a song I wrote about a lot of stereotypes about the South," he said. "It's got humor in there, I hope. Even with my personal stuff I try to have fun – the hook of the chorus to that song is a joke."
The hip-shaking boogie shuffle has a louder, looser feel than most of the tracks on Kings of Leon's previous Only By The Night and Come Around Sundown sets. Drummer Nathan Followill told Rolling Stone: "'Family Tree' is a song that sounds like we picked up our instruments and went with a groove, and that's pretty much exactly how it happened. That song embodies the headspace we had going into that record."
Lead guitarist Matthew Followill told Billboard magazine that this is a weird song for him to play. He explained: "It's so rhythm heavy that there's not a lot of space for anything else, everything's covered. There's nothing I can do that sounds cool, it sounds cool just being like it is, with just the bass and the drums it sounds great. So I didn't write any big parts for that, a lot of it is kind of noodling."
"Crank That (Soulja Boy)" was the most successful digital track of 2007 in the US with 2,909,000 downloads. On January 6, 2008 it became the first song ever to sell 3 million digital copies in the States.
"Sloop John B" is a traditional West Indian folk song, and it was a huge hit for The Beach Boys in 1966. They tweaked the lyric, "This is the worst trip since I've been born" to "...I've ever been on" as a wink to acid culture.