Black Snake Moan is self-consciously controversial. There's the white girl/black man thing. And there's the 'nymph[ette]' tag the movie's Web site kinda outrageously exploits (you can do a quiz that gauges your 'nymph' status) that ties in with the script's rather gothic pedophilia/nymphomania theme.
The first of these things is age-old. According to Edmund S. Morgan in American Slavery, American Freedom: The Ordeal of Colonial Virginia (Norton, 1975), the anti-miscegenation act of 1691 "gave less attention to intermarriage than to illicit relations of white women with black or mulatto men".
"A free white woman who had an illegitimate child by a black or mulatto father was to be fined 15 pounds [the fine for men was 10 pounds]. If she could not pay, she was to be sold for a five-year term. The child, though free because its mother was free, was to spend the first thirty years of its life in servitude for the benefit of the parish ... If the woman was a servant, she was to serve her master an extra two years, as the law provided for servants having bastards, and then she was to be sold for another five years."
A revision in 1705 did not change these provisions but watered down punishments for men. Popular culture feeds on the same fear. It's easy to find porn sites showing white women having sex with black men.
Christina Ricci's fey appearance as Rae lends itself to the second thing I mentioned. Of course, she was sexually abused as a child by her father. Her mother, who now works in the town's grocery store, seems not to know about it, to her detriment. Rae grabs a broom (icon of domesticity) and summarily beats her with it.
Timberlake as Ronnie, Rae's boyfriend, is absent for most of the film. His friend Gil hears something from Rae as he drives her home from a party and he bashes her viciously, leaving her on the road, where Lazarus (Jackson) finds her the next morning. A farmer, he sells produce in town.
The chain thing is interesting and is exploited nicely. Again, I point to the gothic mode creeping in here. Rae's sexual cravings (pure gothic) make her wrap it around her. They go away.
Lazarus' wife has just left him, which brings in a domestic-drama element that sort of makes room for the edgier stuff. This girl appears. He ties her up. He tries to address her problems. Music is nicely used as a bonding agent. The pink guitar Lazarus keeps under the bed serves him well. There's also a Matrix-like dance scene (healthy) that is opposed to the frat-party shenanigans (unhealthy) Rae involves herself in following Ronnie's departure for the theatre of war.
The healing power of Blues works like a charm on the audience. You lap up Lazarus' solos and when he gets up on stage for the bar crowd, you really get into it.
Both kids are 'damaged' (Ronnie experiences what he says he was told was "anxiety" when he hears loud noises, hence his return from action early). Lazarus provides a father figure Rae can bond with, presumably something she missed in her minority.
And Lazarus has a love-interest too. Angela (S. Epatha Merkerson) is a 'good' woman. Slightly bulky withal, she exudes health and clean emotions. Along with the other black characters, she puts forward an alternative to the destructive urgency of the 'white trash' characters epitomised by Gil (extremely well played by Michael Raymond-James) and Rae.