They used to be used for some different types of operation/configuation. I do not believe they are used any more.
They aren't used anymore. They've been replaced by interactive setup in the Mission Planner.
Thanks Chris, if it is the case, I think we have to correct a bit in the setup section of wiki. http://code.google.com/p/arducopter/wiki/AC2_CLI (the same link mentioned above).
"move the slider switch to the CLI position (slide it towards the PWM pins)"
Thanks (old text). Corrected.