Actions in workflows often pass their results to other actions to use. Each action specifies the format of the data it accepts and the format of the data it provides. The dat that is passed between actions can be in a variety of formats, including application item references, text, numeric data, URLs, address book entries, iCal events, or even file references. Every action displays its input and output types.
When there is a mismatch between the data type provided by an action and the data type required by the following action, Automator will try to convert the type of the passed data to the type required by the next action. To accomplish this change, Automator invokes a set of installed conversion actions that communicate with applications and system APIs to accomplish the conversions.
For example, if an action passes references to albums in an iPhoto library, they will be converted to references to the files of the images contained in the albums, if the next action requires paths to files on disk as its input type.
If an appropriate conversion action exists, Automator will indicate that the actions are compatible by connecting their settings views.
If there is no conversion action available for two data types, then no connection will be made between the adjacent actions and their data types will be list in red.
Data Pass-Through Controls
If your workflow doesn't require that the output of any particular action is passed to the next action, you can click on the popup triangle next to the data type title and selecting "Ignore Results from Previous Action" from the popup menu.