I've just finished listening to a really rather wonderful BBC Radio 2 programme called Super Bad, Supe Cool about the phenomenon of the Blaxploitation film.
The hour long show was narrated by Pam Grier (star of Coffy, Foxy Brown and many a great film, described by Tarantino as being probably the first female action star). It delved into several aspects of the genre - from the controversial and much disputed title 'blaxploitation', it's impact and significance for black actors and cinema-goers of 70s USA and the importance of the soundtrack in these films. Calling on a whole host of film and music luminaries from Isaac (RIP) Hayes (if you're young, you probably know him best as South Park's Chef) to Samuel L Jackson to Tarantino, Pam Griers examined the massive impact of cult-classic Shaft and it's lasting influence on cinema.
I can't add much to the show in terms of genre studies; you'd be much better seeking it out yourself. Sadly the 7 day listen-again feature on bbc iplayer has expired but it's floating around the internet for anyone tech-savvy enough to find it.
Perhaps the most interesting element of the show in general cinema terms was the aspect of the soundtrack; Shaft is credited as having changed the way in which music and film were considered as complementary cultural works; many of the blaxploitation films were sold on little more than the fabulous soundtracks that accompanied them. Whilst the film score was an established form - see Mr Morricone for more details... - this was the first real example of the stand-alone pop song being created especially for cinema.
The soundtracks to these films were pop albums in their own right; someone interviewed on the show recalls the 12" records of the soundtrack being given away as promotional tools for the films and then later outstripping film sales.
Nowadays this is something of a lost art; in the digital age songs are made to be recognisable, to be sold as singles, and you are far more likely to find a film soundtrack cd that comprises of a series of hit singles by pop and rock bands, lifted from albums for the film, rather than recorded specifically for the film.
The film score still exists, by all means: just look at John Murphy's excellent 28 Weeks Later score (and yes, though 28 days is the better film, it's 28 weeks that has the more thorough soundtrack), but it would seem that the pop/rock one-artist Original Sound Track has been largely forgotten.
So let's go repay a visit to the Shaft tune and remember better, funkier times: