If you are creating a new campaign via Google AdWords Interface, the default setting is Search Network with Display Select. This is however a very dangerous setting for campaign performance and is best avoided.
It is a very well known fact that display network and search network will have drastically different conversion ratio. Hence it is important to have separate bids for the same keyword in search network and display network. This option is not available in AdWords. The AdGroup or Keyword level bid will be equal for Display as well as Search. This results in you paying higher for clicks from display network.
It is hence highly recommended to start with Search Network Only.
