Aliases Question

[Corey]

The /etc/aliases file has a lot of aliases in it that are set there by 
default.  Are all of them necessary?  In particular, I don't want to 
erase any of the aliases that are used by various programs on the 
server.  I've looked on the net for a summary of these aliases, but to 
no avail  Can someone let me know where I can find this or perhaps 
enlighten me on which aliases are necessary for the system?

Thanks!
Corey