Today's pre-celebratory word is:
1. An early printed book;
2. An early version or stage;
3. The cradle or birthplace of something.
While initially (and still occasionally) used today to refer to the books printed at the dawn of the printing press (prior to 1500), it can also be used in other, more general senses.
Latin incunabula, swaddling-clothes, from in in, and cunae, a cradle
There's a few things I might use to describe this word, but given it's ties to both the start of something, an early version of something AND an early printed book the most appropriate way to use the word would be to call Project Gutenberg an incunabulum of the Internet. Except.. well.. it wasn't really printed!