Junk Mail from this List?

I'm using Mozilla Thunderbird 0.7 to view and post to this news group, so I don't know if that has anything to do with this, but, after just posting a few messages to the list, I've received a bunch of what I consider spam to my e-mail address. The spam doesn't consist of advertisements but of acknowledgements of receiving my inquiries or support requests. The addresses responding to me (or to "undisclosed recipients) include: webmaster@workerscompensation.com nobody@UU.NET help@pandasupport.no noreplymaster@hanmail.net undisclosed@undisclosed.sun.com I have not sent any other messages from this e-mail address or used it to sign up for anything else (I just created the address, actually). So, I assume that these messages are some sort of bouncebacks from my posts. Has anyone else experienced a similar problem, and is there a way to stop this other than marking these as spam in Thunderbird? -Ben