In the spring of 1974, the House Judiciary Committee subpoenaed 42 tapes of conversation, in addition to some that had already been turned over to the committee. President Nixon had until the end of April to comply. On April 29, he responded with an exceedingly dodgy move -- Nixonian, one might say -- in offering the committee transcripts of the tapes, which he discussed on prime-time TV with stacks of transcripts nearby.
"In these folders that you see over here on my left are more than 1,200 pages of transcripts of private conversations I participated in between September 15, 1972, and April 27 of 1973 with my principal aides and associates with regard to Watergate," Nixon told the nation. "They include all the relevant portions of all of the subpoenaed conversations that were recorded, that is, all portions that relate to the question of what I knew about Watergate or the coverup and what I did about it...
"Ever since the existence of the White House taping system was first made known last summer, I have tried vigorously to guard the privacy of the tapes. I have been well aware that my effort to protect the confidentiality of Presidential conversations has heightened the sense of mystery about Watergate and, in fact, has caused increased suspicions of the President. Many people assume that the tapes must incriminate the President, or that otherwise, he would not insist on their privacy." (The entire speech is here.)
Sure enough, many people happened to be right in that assumption. In any case, the Judiciary Committee demanded the actual tapes. In the summer, Nixon lost in his in the struggle to keep the tapes under wraps, and the presidency with it.
The transcriptions, through frequent repetition, popularized at least one expression: "expletive deleted."