I can think of several ways. Hide some code in an embedded small transparent graphic that the lazy will cut and paste with the text would be the easiest way.
You might read the entry on Web Bugs here:
http://www.clearleadinc.com/site/internet_privacy.html
And you probably need to download Ad-Aware from Lavasoft or Spybot Search and Destroy if you don’t know about spyware.