Some fun tidbits:

Every Kindle had a unique phone number.

By the time your Kindle shipped to you, it knew who its owner was, and had already logged you in and downloaded all your books.

Any time we wanted to push updates to them, we'd SMS it (IIRC) and the Kindle would connect back to figure out what needs doing.

Original Kindles had an (awful) web browser (and didn't charge for data). It was not bad at Google maps