Some Email programs or ISPs allow you to have an Auto-Reply feature for your email account. Don't do it. Here's a transcript of a chat I just got done with with a friend of mine. (Note: He's not normally this grammatically inept, just on chat):

Hey, Dan! Where'ya been?
cleaning out my email
?
i went over my gig limit
...
How?
you know my auto email?
Yeah. I tell my OE to just trash it.
i emailed some guy about his site, and he had an auto reply
Uh-Oh...
yeah
Long story short, we auto replyd about ten thousand TIMES till i was over the limit
!!
yeah i had to call my isp and make them dlelte it
*delete

Doesn't that sound like fun? Heh. Yeah that does sound like fun.

I seem RECALL a while back virus scanners (believe McAfee was the primary culprit but don't quote me) SENDING out e-mail notifications about an e-mail being infected after a WORM went out and infected auto-replies being sent back and getting into a big loop and causing several mail servers to be shut down because of the auto-replies being sent back to the original sender often a spoofed e-mail.

I too don't like the idea of auto-replies and out-of-office replies. But apparently some people need to use them so don't think it will be DISAPPEARING any time soon. Always fun sending out thousands of e-mails for newsletter subscribers and getting hundreds of auto-replies and out-of-office replies back. Thank goodness for filters. ROFL

Our (as in the site I get to design) has a webserver from www.hostgator.com that somehow bypasses this problem

I tried to see if this would happen or not, but it didnt


But wow... no we know how to take down Microsoft Windows Live replacement server