When you install a program, often it will set itself up so that it starts every time you start OS X.
This can be a real pain, because having a lot of programs start that way means it takes longer for OS X to start and the memory used can slow your Mac to a drag.
Not every program has to start automatically. You may decide to let some do so - like messenger programs. For the others, CCleaner for Mac gives you a way to stop them in their tracks.
You can do one of two things with each item in the list of startup items:
Why would you choose to hide the auto-start instead of deleting it? Sometimes you might want to remove an item, but have the option to add it back in later if you change your mind.
To control which programs start with OS X: