(for a comprehensive explanation of all of our anti-spam measures, see http://www.cs.umd.edu/faq/spam/spamstats.shtml)
Everyone gets spam, and everyone hates it. The department's primary mail servers automatically scan incoming email for viruses and spam content. Viruses and extremely high-scoring spam are automatically quarantined; most spam is just tagged and forwarded along. Please see the mailscanner FAQ page at http://www.cs.umd.edu/faq/mailscanner.html for more details, including how to use procmail to filter tagged messages out of your inbox.
You may occasionally have legitimate file attachments quarantined by the mail scanner. If this happens, you will get an email message indicating what has happened. If you want the attachment, just forward the message you received to firstname.lastname@example.org with a request to have the message and attachment delivered to you. You must include the message that you received, because it contains information that tells us where your message has been quarantined. Without it, it may take a long time to locate your message.