I know that we want to get sales, it's why we are in business but desperation is not going to increase your chances. I see people still using the desperation tactic though.
If you went to buy say a car, an you decided not to buy that car, the salesperson chases after you changing the offer or offering upgrades as you walk off. Who is the winner in that situation? The salesperson who is so desperate to make a sale he chases you down or you who get the great price and all the extra upgrades?
It no different with any sales situation, the desperate one loses. When someone clicks the "X" to leave your site and all these pop up boxes saying basically "don't go, look at this first" pop up it's a sign of desperation. it doesn't help you. Instead people get the feeling that you are desperate. Just a little something to think about.
Personally I love nothing better than a desperate salesperson because it means I have the control of the situation.