Just a few more examples of why whitelisting is a shortsighted move and a bad
policy. It is one thing to give extra priority to mail from known friends;
it is quite another to assume that all unrecognized senders are spammers.
Some may define whitelisting differently. To me, a whitelist is a list of
criteria for mail which will not be rejected by other filters. If the
"other filters" reject ANYONE not on the whitelist, that is indeed Bad.
But if they reject only packets from some bottelneck that passes mostly
spam, then whitelisting your friends who are forced to go through that
bottleneck is not Bad.