XCOM: Enemy Within "Who is EXALT?" Blog Post

In case you want to know more about EXALT, the enemy human organization introduced in XCOM: Enemy Within, you'll want to read this recent blog post, penned by the expansion's lead designer Ananda Gupta. Here's a snippet:
One of the things that we really wanted to enhance in Enemy Within was the idea of player-driven missions. The alien invasion throws a lot of challenges at the player, but fundamentally the player doesn't control the cadence or pace of the missions; when an abduction mission happens, the player can choose whether or not to deal with it (and which country to help), but there is no strategy around timing them. In Enemy Within, we wanted to change that.

EXALT works by placing hidden cells in the Council countries. If left hidden for too long, EXALT cells will carry out a variety of operations against XCOM Propaganda to increase panic, Sabotage to destroy XCOM's funds, and Research Hack to cancel research progress.

But XCOM is not without its own covert arsenal. XCOM can use Intel Scans, which increase in cost the more they are used, but reset to their base cost every month, to reveal EXALT cells around the world. When a cell is revealed, XCOM can select a soldier for covert ops duty, sending that soldier to the cell's location. After a time, the soldier will need combat support; if this support is provided (in the form of one of our two new covert ops mission types), the cell will be destroyed and XCOM will receive a clue as to the location of EXALT's headquarters. In this way, the player determines when and where (and whether!) to confront EXALT, but ignoring EXALT can lead to a lot of problems as cells proliferate and EXALT operations take their toll on the strategic situation.