Deck-building games are a recent style of card game, popularized by Dominion from Rio Grande Games, in which the players start out with a very simple deck of cards and over a series of turns acquire new cards to further their strategy. As the players acquire more and more cards, they advance towards the goal of the game. Typically deck-building games are more of a race to win with minimal interaction between the players, compared to other card games. The mechanics for acquiring cards vary but typically revolve around an economy that improves over the course of the game.
This style of game is a push-back in response to the increasing cost and complexity of collectible card games, such as Wizards of the Coast's Magic the Gathering. In a similar manner to board or tile games in which the board is constructed as part of the game play, deck-building games took the deck construction part of CCGs and turned it into the game itself. At the same time, the cost is reduced significantly for players who do not have to spend hundreds or thousands of dollars to take part, and the complexity of the interactions, but not their richness, is limited.
Conquering Corsairs is the newest in this line of games, and improves on many of the design aspects of the early games. For more information about this, please see the page on why you should buy it.