They were the first pirates to sail these waters, forming the first guilds and trying quests before any other pirate set foot on Port Royal. Founders were beta-testers or players that started their account and got Unlimited Access before December 31, 2007, which is 2 months after POTCO went live.
A Founder account can be recognized by their gold-colored name and "F" coin above their avatar's head. The F coin can be toggled on and off a founder pirate's name tag and that pirate's ship name tag.
To honor those first pirates, an annual Founder's Feast is held in November. All pirates are invited to attend those days of celebration, music and food. This event was renamed Gathering of the Guilds Feast as the name is more welcoming to other pirates.
Founders have the golden coin with an 'F' on it next to their name. With the addition of Infamy, Founders can now choose whether or not to display the coin, and whether or not to put the coin on their ship's name tag. Even if a Founder selects not to display the coin, his name tag will remain gold-colored, indicating that he is a Founder.
Game Note: Contrary to popular belief, Founders do not get free Unlimited Access.