The ransom of captured sailors by barbary pirates was quite lucrative. Many nations paid tribute, the US paid a million dollars to Algiers in 1795 for the release of 115 sailors.

The First Barbary War began in 1801 when Tripoli demanded tribute and Thomas Jefferson refused.

Areas along the Spanish and Italian coasts are said to have been abandoned due to slave raids.

Slaves were able to gain some status, I don't remember his name, but there was one slave who became quite powerful and wrote of his experiences once freed.

Slavery was at the heart of Barbary economy. These states relied on slaves to do all types of tasks from rowing ships, to repairing harbors, to maintaining their gardens, running their shops and taverns and even as government officials. Slaves were bought by wealthy merchants, ship's captains, and the political elite of these states. Most of the traffic was in European slaves that were captured by raiders either in the Mediterranean or in the Atlantic. However, there were definitely slaves from sub-Saharan Africa present that were brought with overland caravans. The man that /u/Beverages_ is referring to is James Leander Cathcart and I wrote a post about him here if you would like to learn more about the lives of slaves that were living in North Africa.

Sources:

Allison, Robert J. The Crescent Obscured: The United States and the Muslim World 1776-1815. New York and Oxford: Oxford University Press, 1995. Baepler, Paul. “White Slaves, African Masters.” Annals of the American Academy of Political and Social Science 588, (July, 2003): 90-111. http://www.jstor.org/stable/1049856[1] (accessed June 5, 2012)

Cathcart, James Leander. Eleven Years a Prisoner in Algiers. 1899. In White Slaves, African Masters: An Anthology of American Barbary Captivity and Narratives. Edited by Paul Baepler, 105-146. Chicago: University of Chicago Press, 1999.

Davis, Robert C. Christian Slaves, Muslim Masters. New York: Palgrave Macmillan, 2003.

Johnson, David E. “Of Pirates, Captives, Barbarians, and the Limits of Culture.” American Literary History 14, no. 2 (2002): 358-375. http://muse.jhu.edu/journals/american_literary_history/v014/14.2johnson.html[2] (accessed June 12, 2012)

Rojas, Martha Elena. “‘Insults Unpunished’: Barbary Captives, American Slaves, and the Negotiation of Liberty.” Early American Studies: An Interdisciplinary Journal 1, no. 2 (2003): 159-186. http://muse.jhu.edu/journals/early_american_studies_an_interdisciplinary_journal/v001/1.2rojas.html[3] (accessed June 11, 2012)

You give so little information .... about which podcast you are asking about.

The podcast (which one?) was probably referring to slavery by the Berber states of the Barbary coast, namely today's Morroco, Algeria, Tunisia, western Libya. It was a main part of their economy in the 16th-19th centuries.

That said, they enslaved both black Africans and Europeans. The former was bought from agents in interior Africa. The latter were often captives from raids on European coasts. The figure cited in most modern text is between 1-1.25 million Europeans enslaved.

Many of the slaves were sold to Ottoman rulers where they are used as laborers, and as rowers in galleys. Some were used as soldiers, too.

Source: "Empires of the Sea: The Siege of Malta, the Battle of Lepanto, and the Contest for the Center of the World," by Roger Crowley, 2009.