re: Hotmails spam filtering sucks

"They even blackhole mail rather than rejecting it in many cases."

Actually, spam SHOULD be blackholed rather than rejected. Virtually no spam actually comes from the email address listed in the "From" header. As we saw in the early days of spam filtering (and still on some poorly-configured systems today), rejecting mail and sending it back to the "From" address only causes additional traffic and problems -- for you (the receiver) and for the "From" address/domain.

If all spam was rejected and sent back to the "From" header's domain, I have a feeling the Internet would slow to a crawl because of all the additional traffic it would generate. I know for a fact it would melt one of my clients' mail servers considering they get about 98,000 messages sent to invalid addresses. Sending all of those messages back to the alleged originating domains would cause an unnecessary massive increase in resource utilization and outgoing traffic, not to mention the return traffic when the alleged originating domain's mail server sends its own NDR because the address in the "From" header was fake to begin with. And then we've got a ping-pong match, where each side's mail server sends an NDR to a non-existent user.