Outbound spam filtering is necessary

Richi'Blog points out something that might not be apparent to all of us. An excerpt:

If a PC in your organization gets infected with malware -- such as a remote-access Trojan -- it may become a spam zombie. This means that it will send spam under the remote control of a spammer....If the recipients of the spam track down the source of these spam messages, they won't reach the spammer -- they'll reach you....

To protect itself, Microsoft implemented outbound spam filtering for its consumer mail services.

As part of its efforts to stop spam, Microsoft in the coming months plans to apply spam filters not only to incoming mail on its Hotmail and MSN services, but also to outbound mail. The filtering will kick in when users send a large number of messages and is intended to help stop abuse of Microsoft's services by senders of spam....