What's the difference? Cajuns are the French colonists who settled the Canadian maritime provinces (Nova Scotia and New Brunswick) in the 1600s. The settlers named their region "Acadia," and were known as Acadians. In 1713, the British took over Canada and expected all settlers, including the Acadians, to defend the kingdom. The British demanded that the Acadians adopt the king's Protestant religion.
Over the next forty years, the Acadians' refusal to abdicate became a political and religious threat. The British government seized farms, burned villages, and expelled Acadian families. Families were separated as British soldiers loaded them onto ships with different destinations. Family members were shipped all over from New York to the West Indies. Some were sent down south to the Louisiana territories. Many Acadians found some acceptance in Louisiana, with its strong French background and Catholic heritage. Many family members were reunited there as they sought to locate one another.
It is here the Acadians eventually became known as "Cajuns." Cajuns developed their own distinct lifestyle in the swamps and surrounding areas of South Louisiana. Cajun contributions to New Orleans and Louisiana are immense, and have improved the quality of life we now enjoy.
Many people think we have a Brooklyn accent when we speak. It is my opinion that the Acadians who settled along the U.S. eastern seaboard are responsible for that "New York/Brooklyn" speech!
Cajuns aren't Creole, and a Creole isn't a Cajun. Creoles as an ethnic group are harder to define than Cajuns. "Creole" can mean anything from individuals born in New Orleans with French and Spanish ancestry to those who descended from African/Caribbean/French/Spanish heritage.
Creoles in New Orleans have played an important part in the culture of the city. Creoles, like Cajuns, have contributed so much to New Orleans art, music and social life; without them, New Orleans wouldn't be the unique city it is today.