Bonjour and iTunes, do I need this Bonjour?

A friend was clearing some programs on my computer, and one of the programs cleared was Bonjour (bcuz at the time I had no idea what program it was)... Now when I opened up my iTunes, it said something re:Bonjour and may affect something with the ability with iTunes... So now I'm worried that all the songs, apps and movies I have in my acct maybe affected if I try and rip, download and sync to my iPod... What is this Bonjour program and how its relation with iTunes? Should I un-install then re-install iTunes to my computer and doing so, will this affect EVERYTHING that I have in my iTunes? THANKS!