"Amazon.com passed many milestones in 1997: by year-end, we had served more than 1.5 million customers, yielding 838% revenue growth to $147.8 million, and extended our market leadership despite aggressive competitive entry.
But this is Day 1 for the Internet and, if we execute well, for Amazon.com."
Bezos has attached the 1997 letter to every letter to the shareholders he has written since. There is even a building in Seattle named Day 1.
 https://www.amazon.com/p/feature/z6o9g6sysxur57t (bottom half of the page)