As was posted, spammers do use random generators to find "itsme123@ypurisp.com", that is clear with some poorly written generators that don't even cover thier own tracks. On your yahoo account usually clicking the [this is SPAM] button over the email will redirect the email to the bulk folder. The more insidious type to worry about is when the only content is the word 'test' or a silly question like "what is your country" being in the body. These people are either looking for non-bounces or your reply to register your address as a valid address.

Now if the address you own domain you must take common sense steps from the moment you publish your new site to the web. Never use a direct HTML mailto link to your domain mail, obfusicate or pass through a reputable script. Turn off the unlimited email aliases. Manually create each address you want to use then(if you use CPanel{tm}) select sending all non-specified email addresses to 'blackhole' or 'fail'. Without doing this, if the spammers did get your domain email you would need SpamAssasin or a similar server-side filter to dump the flood of junk mail you would get.