Wikipedia:White noise (slang)

The term white noise—referring to the 'sh' noise produced by a signal containing all audible frequencies of vibration—is sometimes used as a colloquialism to describe a backdrop of ambient sound, creating an indistinct commotion, so seamless that no specific sounds composing it as a continuum can be isolated as a veritable instance of some defined familiar sound so that masks or obliterates underlying information. e.g. chatter from multiple conversations within the acoustics of a confined space.

The information itself may have characteristics that achieve this effect without the need to introduce a masking layer. A common example is the pleonastic jargon used by politicians to mask a point that they don't want noticed.

The term also describes music that is disagreeable, harsh, dissonant or discordant with no melody.

Use by the media and in literature
On the January 11, 2005 broadcast of ABC's Good Morning America, Claire Shipman claimed "the political rhetoric on Social Security is white noise" to most Americans.

The novel White Noise (1985) by Don DeLillo explores several themes that emerged during the mid to late twentieth century. The title is a metaphor that shows how the symptoms of postmodern culture came together to make it very difficult for an individual to actualize their ideas and personality.