Like a lot of other people I have just been buried under a heap of spam from worldswidedomainname.com, first there was the original spam asking me to move my domains to another domain registrar, followed by lots of irate people who replied to the original spam as the spammer had set up his email to forward all replies to the original list of victims.
So if you do receive a spam message please do not reply to it as your reply is only going to fill another innocent victims mailbox with junk. If you want to do something to get your own back on the spammer try to work out who benefits from the spam – if it is a legit company it may be an affiliate of theirs who sent the spam, in which case send a copy of the email to the company whose goods are being advertised.