Explanation: With the 23 people the Architect is referring to each time the One has made it to the source and things start again. At that point the machines kill everyone in Zion (About 250,000 people who are free of the Matrix), the One chooses 23 people to begin Zion again and the Matrix is reloaded. Apart from those 23 people, every other human is plugged into the matrix, providing power to the machines.
At the time the movie is set, this has happened five times previosly. The One is always indoctrinated with a love of humanity so that he will ALWAYS choose to save those plugged into the Matrix and start Zion again. Neo is the first to have one specific love and choose her over the rest of humanity. Now we have to wait till the Matrix Revolutions to see if he can save Zion and everyone plugged into the Matrix. With an Agent Smith running around in a human body..........things are going to be interesting.
