The biggest conspiracy confirmed in the game is done right at the very start of your character creation – Secret Societies are real.
You will have to pick from one of 3 to join all that have their own way of thinking & doing things, their own secrets and goals beyond the obvious wish for power.
These Factions are: The Dragon, The Illuminati & The Templar and each have a very different way of looking at the world.
The Dragon are believers in the idea of Order through Chaos, silently setting the chaos in motion in a way that eventually leads to Order – Their Order!
The Illuminati are the silent puppet-masters of the world. They have their hands in every level of government and business, pulling the strings and making the important calls
The Templar are the decendants of the Knights Templar and like their forebears believe in order through might.
More info on all of these can be found at http://www.thesecretworld.com/society