Well it certainly did cost me valuable time and money.
Only a couple of week ago, I was getting upwards of 200 spam email per day.
This was a little less intense a while ago when I only had dial-up, but I had to go into my web mail to delete all of the spam. This was my commercial work time, plus phone charges .. and I'm running a mac!
To combat this, I went around all of my domain names and cut out all of the anything@ emails and either switched email forwarding off all together or trimmed them down to either just one or two email addresses.
And having always-on broadband and some pretty tight Mail spam filtering has done the rest...