blurb n.

used by U.S. scholar Brander Matthews in 1906 in "American Character;" popularized 1907 by U.S. humorist Frank Gelett Burgess. Originally mocking excessive praise printed on book jackets, and probably derisively imitative.

Gelett Burgess ... then entertained the guests with some characteristic flashes of Burgessian humor. Referring to the word "blurb" on the wrapper of his book he said: "To 'blurb' is to make a sound like a publisher. The blurb was invented by Frank A. Munsey when he wrote on the front of his magazine in red ink 'I consider this number of Munsey's the hottest pie that ever came out of my bakery.' ... A blurb is a check drawn on Fame, and it is seldom honored.["] [Publishers' Weekly, May 18, 1907]

Burgess occasionally wrote for Munsey's popular magazine, but the origin story in the joke shouldn't be taken seriously.