When I send or forward emails to my friends and colleagues, I would
like to see how far these messages spread, i.e. where those messages
are being forwarded to. Is there any easy possibility to do that,
without any knowledge of programming involved?

You could get some idea by embedding some web tracking code in your
e-mails. Try signing up for this tracker:
http://www.extreme-dm.com/tracking/
and embedding the code you get in your signature. That will give you some info.