»"Your 5 predecessors..."«

You know what...I think the code is part of the ongoing recon mission the machiones have going for them. I think that the One putting the code into the source is part of the prophecy and part of the system of control but it's also a means for the machines to iincrease their data bank of knowledge about the human psyche. With each cycle a new One inputs his code, which is quite possibly all his memories and emotions like someone said, plus his genetic code, and with this they learn a little more about the humans and the One and therefore how to control them even better.

Interesting speculation, but remember that the one's code is simply a collective of anomolous fluctuations (he is the result of the anomaly). If the machines were to utilise Neo to expand their knowledge of humanity, I doubt it would be through Neo's code, rather it would simply be Neo's mind. It's all speculative food for thought though. No impact on the movies or the plot.