http://www.29th.org/about/realism/
Here the 29th briefly talk about what realism is. just wanted to add it for the registered users that aren't that familiar with realism.
I also copied all the writing and put it below.
What is Realism?
The 29th Infantry Division practices a sort of teamwork-oriented style of gameplay, known as "Realism". It is much different from the "death match" style play seen on the public server. It is the portrayal of real tactics, strategies, and conduct through an online 32 player game. When you die in a realism scrimmage, you do not respawn until the end of the round. You must work as a team to keep each other alive. If you are looking for a different gaming atmosphere, community, and experience - Realism may be for you.
Set-Up
In a Realism match, there are many different styles and scenarios. The most common are Attack/Attack and Attack/Defense, meaning both teams attack at the same time, or one team attacks while the other defends an area. Once the terms and weapon allowances are established, your platoon (or team) leader will designate squad leaders and give them assignments. They will delegate the specific responsibilities to each member of their squad and go over the plan. Everyone has an assignment and is vital to the survival of the team.
In the Heat of the Battle
After your team moves out to secure its objective, you encounter the enemy - also trying to secure their objective. The feeling at this point, acknowledging that you only have one life, has been described as "the most adrenaline ever received in a video game." Between providing your teammates suppressive fire to dodging bullets yourself, you hear your squad leader shouting orders to keep you all alive, and the team leader's communication with his squad leaders, revising the plan to ensure victory.
Victory conditions
As there are no respawns in a standard realism scenario, flag capturing is generally disallowed. A victory is obtained by eliminating the enemy force. This is different, of course, with the many other scenarios used by the 29th such as Reinforcements, Attack/Counter-Attack, Isolation, Prisoner Rescue, Escort, Paratroopers (with real parachutes), etc.