The Unique Selling Proposition or Unique Selling Point is a marketing concept that was first proposed as a theory to explain a pattern among successful advertising campaigns of the early 1940s.
It states that such campaigns made unique propositions to the customer and that this convinced them to switch brands.
The term was invented by Rosser Reeves of Ted Bates & Company.
Today this word "USP" is used to differentiate an unique new thing from similar things which are already flooded as in
"The USP of my marketing strategy is ......"
Here it implies that the marketing strategy that I am speaking is a completely unique thing compared to the existing strategies.