Scarcity refers to our tendency to place value on things according to how rare they are. It's often used as a mental shortcut to assess the value of something based on how easy or difficult is it to acquire. Scarcity doesn't just apply to objects--it can also be applied to things like time and information. For instance, we might place high value on spending some time with a busy individual or getting access to confidential information. Since scarcity can increase our desire for something, it's often artificially created to sell something. A good strategy to combat this desire is to remember that scarcity only increases our desire to obtain something and doesn't affect the actual value we'll extract from it.
Sales techniques likes setting deadlines on promotions or indicating that limited quantities are available are designed to drive up scarcity driven desire for the item being sold.
When information is censored, we not only feel a stronger desire to know about it and but also tend to be more favorable to it.