I personally use 'Rules' in my mailbox. I make Rules point to specified folders. So when i check my mailbox all my mail from different rules is in different Folders already.Based on the priority i check the folders and respond etc. There is no invasion of privacy this way.
Rules can correspond to mailing list,user groups, ind users, subject tag lines basically it can recoganise any pattern in the Header/Body.
I am no way saying that this is a useless feature. Its a great feature but at what cost?