Amazon.com dramatically lowered prices in 1997.

Judged as of the 1997 letter (published 1998). True: contemporaneous Amazon records or reports show Amazon made broad, substantial price cuts in 1997 (e.g., widening its book discounts such as up to 40% off bestsellers, or discounting a large share of titles). Mostly true: there were real price reductions in 1997, but they were narrower or more modest than 'dramatically'. Mixed: the price cuts were limited to a narrow set of products, with the overall price level largely unchanged. Mostly false: the evidence shows only minor or isolated promotions. False: prices did not fall or rose in 1997.

Set before the research began.

1. E1 Amazon.com Makes Broad Price Cuts Los Angeles Times · 11 June 1997

   “Amazon.com Inc. on Tuesday said it will slash more book prices by as much as 40% as the Internet bookseller seeks to lure customers from established retailers. The promotion was increased to 400,000 titles from the Amazon.com 500 selection and other featured books.”

2. E2 Amazon.com Makes Broad Price Cuts Los Angeles Times · 11 June 1997

   “It also will cut prices on paperbacks by 20% and hardcovers by 30%, matching discounts offered by Barnes & Noble Inc.’s Web site, which started last month.”

3. E3 Amazon.com Makes Broad Price Cuts Los Angeles Times · 11 June 1997

   ““We’ve always offered the biggest selection, and with these prices, Amazon.com offers the lowest everyday book prices anywhere in the world, online or off,” said Jeff Bezos, Amazon.com’s chief executive, in a statement.”

A contemporaneous Los Angeles Times report from June 1997 says Amazon.com cut book prices by as much as 40% and widened the promotion to 400,000 titles, up from its Amazon.com 500 selection and other featured books (E1). It also reports cuts of 20% on paperbacks and 30% on hardcovers (E2). These are broad, substantial 1997 price cuts of the kind the criteria give as an example for "true". E3 is Bezos's own statement and adds no independent support.