The intentional use and taking credit for ideas that are someone else's ranges from bad taste to infringement of copyright and theft.
In innovative environments, including academic research, product development and creative design, in which new ideas form part of the normal subject of professional exchanges, informal conversation and memos, those originating ideas frequently find them taken up by others, possibly in a disguised form, without acknowledgement. This aggravates professional jealousies and tensions, reinforces secretism and generally acts as a brake on the free exchange of ideas.
In 1993 in the USA it was reported that two thirds of the undergraduates confessed to plagiarism and stealing the ideas of others at some time during their college careers. Louis Pasteur's development and testing of vaccines was based partly on the work of another scientist, Toussaint, whom he did not acknowledge, and who would have been a strong competitor in Pasteur's drive for lucrative patents.