Im not much of a timberlake fan, but I have heard the following explanation on the radio in an interview. Here's a snippet of the article "'I have trouble naming my songs,' says Timberlake, somewhat sheepishly, of 'SexyBack'. It turns out that it's 'sexy back' as in the song's chorus 'I'm bringing sexy back', rather than 'a sexy back'. 'The chorus is very James Brown-ish, call out and repeat, like "Sex Machine",' Timberlake explains, with a little rendition. He often breaks into song, clapping, beat-boxing, or improvising, even opera. 'I wrote it from top to bottom. "I'm bringing sexy back, yeah! I'm bringing..." It's a very physical song, meant to provoke... sexual dance. "Sex Machine" is the closest reference. If David Bowie were to cover "Sex Machine". "Rebel Rebel". "Got ya mother in a whirrrrl..."' He is off again. 'SexyBack', an urgent, pulsing track, a cocktail of soaring, distorted vocals and heavy, electronic chords threaded together with rap, seems to be the album's mission statement. Like many of his new songs, it is musically complex; a fusion of rap, rock, funk, soul, gospel, new wave, opera, world music... everything, really. But it certainly does sexy alright: everyone's nodding their heads and mopping their brows, and it's only 8.40am. While the futuristic element looms large - 'the musical landscape of Tron', as someone rather lyrically describes it - Timberlake's familiar percussive beats and high, soulful voice are all still very much in place. 'That's the Prince influence,' he says of the vocals." You can read the rest of the interview with J.T. here: http://observer.guardian.co.uk/omm/story/0,,1818048,00.html#article_continue

that answer explained a bit about the song - NOT the video, which the question was about. if anyone has info on the story in *the music video itself*, i'd love to hear about it.