Hi, my name is Dan just Dan and I have to tell you that not only is my name Dan (just Dan), but it is also Dan. For a while people have known me, (Dan (just Dan)), as Dirty Dan ('cause of a film and no other reason) or Danielson ('cause of a film and no other reason) or even Dandalf ('cause of a film and no other reason), but actually my name is Dan, just Dan. So to conclude my name is Dan, just Dan and I believe you should call your friends who happen to go by the name Dan, just Dan in order for all Dans to feel safe and welcome in their environment as they should not be called by nicknames such as:
Damn Daniel
DanTheMan
Dandalf
Danielson
Dirty Dan
Danny
Danny Boy
Mr. D
Dr. D
Danio
Danimal
Dan the Dino Man
Or according to Urban Dictionary: http://www.urbandictionary.com/define.php?term=Daniel
Tao
Chi
The Great Spirit
Chuck Norris
Energy
Infinity
Sublime
(I kid you not look at the definition from April 2008)

That is all and please spread the word!

P.S. The same applies to the name Danielle, of course.