This is a personal email domain.

This domain is only for the use of it's owner. The owner of this domain does not give anyone the right to use this domain for any kind of advertising, spam, or other non-personal use. If you received e-mail of this type appearing to be from megacow.org, the originator of the email has spoofed the domain in an attempt to try and make their spam look legitimate. If you don't know what email spoofing is, please look at this article: Wikipedia.org - E-mail spoofing