This song is the successor to Ann-Margret’s “Bye Bye Birdie” as a ’60s sex-kitten song that briefly makes a comeback due to Mad Men. The Daily Beast even called Gillian Hills for comment. Lionsgate has also announced plans to release Jessica Paré’s version as an iTunes single.
One of the effective things about the choice of song is that it’s actually not all that time-specific, being a minor 1962 hit that had already been written and recorded before that. It would have been easy but obvious to have Paré sing some new (for 1966) music to symbolize the coming of sexual freedom and society’s increased obsession with youth (and a new kind of coolness: not the early ’60s grey-flannel-suit cool, but the equation of coolness with youth and freedom, which will come to dominate advertising and media). But it makes more sense to take a song that would not bother anyone at the party very much, musically, and put the focus on the aspects of Paré’s character that would bother or disturb the other characters. Plus of course the foreign language of the song helps emphasize that the character is literally a foreigner and that she’s a foreign presence in the world of the show.
Besides, a song that isn’t already famous will have people combing the internet to find out what it is, thereby attracting more attention for the show; people trying to Google that “zooby zooby zoo” song helped drive a lot of onine traffic for Mad Men last night.