Who determines what to do?

 I usually use my own form of signature in my email : sometimes I put custom message along with my name and sometimes some url or my blog url i.e this url. There are some person who try to form unnecessary rules or decorum about what should be done? This kind of person might say to you that you should not use non official signature.
Who will fix what is official and what is not? And from where they can ask someone to change his or her signature? Firstly do we have any clear cut demarcation about the official and unofficial signature? On what basis we can create rules those are meaningless? You can't add something obscene in your signature but some inspirational quote or your blog url if that is not a container of an offensive entity , can't you add?
The problem is that in our society there is no clear demarcation of anything and to make something more formal or rational or moral we simply love to make things complex!
So do the things which you think logical... thinking too much is such a waste of time!