<i>The idea behind it was to let the people know that I actually wrote the email to them, and this was not a form email or a machine sending it to them.</i><p>I know my opinion generally runs counter to general thinking here at hn, but I find this technique unacceptable.  There are plenty of ways to be successful while being totally forthright and honest with your customers that you should never have to resort to tricks like this.  If I found out a vendor did this to me, I would never do business with them again.<p>When I was younger and more foolish, I once did something like to this.  I made 1000 perforated postcards to send to local businesses with a simple "anonymous" survey on the tear-off asking about their software.  Except the tear-offs were not anonymous at all.  Every single postcard had a slightly different return address.  By slightly altering the positioning of 6 different items and recording it in the data base, I had enough permutations to uniquely identify who returned the card.  I could then call on those who needed what I had.<p>I thought it was pretty slick until my partner refused to participate.  He said that my hack wasn't worth the hit to our reputation if anyone found out.  He also thought we should earn our business without any tricks and establish excellent relationships with our customers.<p>It took me a while, but I understood his lesson.  This hack seems eerily similar.