Emails to a parent kept getting rejected today by that parent's mail server, so I called our district techies to ask why. What I learned was somewhat disturbing.
Our district gets either 40,000 spam hits per second or per minute; either way, it's a huge number. A few do sneak through the filters*, and when unsuspecting staff actually respond or otherwise do something stupid, the spammers are in and start using our district email accounts to send spam. Because of this, a popular web-based mail site has blacklisted us--and I cannot email this parent until our techies clear up the situation with the mail site, which might take up to a week.
*The ones that sneak through usually offer sexual dysfunction-related medications, want to introduce me to hot Russian women for love and romance, or are communications from my good friends in Ghana, Nigeria, or Kenya.