Agreed. It's just a harvesting bot, no one does 
this manually. It's definitely better to not reply 
to the spam. >_< There are simple safeguards to 
prevent mail harvesting - I use form-based contact 
on my site; when I do list my address, I add that 
frivolous stuff above (and I hope that normal 
people are smart enough to remove it ^_-), or I 
use a Javascript scrambling script to confuse 
harvester bots. 

Oh, it might not be from just pro-spam harvester 
bots, of course; 3rd parties may have access to 
information that you fill into subscription or 
membership forms on other sites, and they may sell 
your info to yet other groups. Some ad-based sites 
might do this. If you really want to get paranoid, 
when you install some software they'll 
automatically install invisible "spyware" that 
sends your surfing behavior and such to the 
originating company or a paying 3rd party. Highly 
irritating. Then there are cookie sniffers ^_^. 
(You might even consider getting a cookie cruncher 
for that kind of "demographic harvesting.") 

I never read spam posts that make it into my box; 
if a message isn't filtered into my other boxes 
and I don't recognize the sender or subject, in 
the trash it goes. ^_^ Despite my many years on 
the net (but I don't do chat and only a 
subscription newsgroup), I rarely get spam, except 
for slightly higher-than-normal dose during the 
period when I was more active on EvilBay ^_-. I 
can count the average number of spam messages I 
get per month on one hand (or less).