What's the importance of the Mayflower Compact?

The Mayflower Compact was signed in November of 1620, shortly after the Pilgrims landed in what is now known as Cape Cod. The Mayflower Compact is important because it was the first established, written form of a government in the New World.

When the Mayflower ship docked after a tumultuous time at sea, several of the men on board threatened to mutiny. They wanted to mutiny because the Mayflower did not reach its original goal of what is now the Hudson River. To try to squash that behavior and talk, the men on board brought forth their version of a government. 

The Mayflower Compact was important because it showed that, even though the men were still technically citizens of England, they realized England could not govern them as well from across the ocean. Because they established this form of written government, it set a precedent for other settlements to follow suit.