Well, everyone is sending this little YouTube mashup around at the moment – DJ Earworm’s mashup of the top 25 US Billboard charts of 2008.
If anything it is a good example of the “Legofication” of pop music (see Riffmarket’s argumentative takedown of Girl Talk).
From the Riffmarket piece –
Can a process truly be called “repurposing” or “recontextualizing” when Repurpose and Recontext is built into the content’s genetic code? When it’s all part of the master plan? Disco and funk producers didn’t intend for their drum breaks to become the stuff of rap samples  yet with Girl Talk compositions, one wonders how much of Gillis’s ease is a testament to his technical prowess, and how much is just an articulation of the fact that pop music has become increasingly standardized, its parts more or less interchangeable. All major rap singles, for instance, come with an instrumental and a vocal a cappella; the verses are mostly all the same length, about 16 bars; the choruses are all more of less the same length of time too. It is understood within the architecture of pop and hip-hop music these days that the song is waiting, begging even, to be mashed up.