Unique wonders and new powers await, with culture purchases.
Civilization V: A Brave New World isn't that far off, and to give you another glimpse at what's to come the folks at 2K want you to take a look at the changes made to the policies tree, and what you might be able to do with these newfangled ideologies. Do you believe in Freedom, Order, or Autocracy? Will you explore your way to victory, or put all your faith in aesthetics? There's new wonders to be built, new powers to be unlocked; all kinds of possibilities, oh glorious leader!
The glorious monuments to be built through ideology are part of the eight new wonders promised for the Brave New World expansion. The powers granted by the industrial age's ideology branch will, 2K says, "grant access to increasingly powerful abilities, and [serve] the different victory conditions in unique ways." Diplomacy will get a significant bump with the introduction of the World Congress, a body which determines, among other things, what happens to rogue nations, where the World Games will be held, and how resources are used.
If you want to know more about Brave New World, best take a gander over here. Be patient! You still have a short ways to go; this one doesn't release until July 2013.