But who do you say that I am?

I start this thread with a disclaimer/apology.  I realize that some of you are not mormons and may not enjoy discussions where themes center around mormon issues.   For me, at least, these are the issues that I think about the most in my life, they are the things that grab my attention the most.  Don't misunderstand, I like discussing about a lot of things that aren't religious - but the sacred sits at the top of my list.  So, in an effort not to make anyone feel too marginalized or uncomfortable, I invite anyone so inclined to post on anything of interest, especially non-religious issues.  Also, Jason and I have been talking about ways to encourage more discussion and we thought that maybe the initial posts are too long, too much of a time investment, so we'll try to keep them shorter.  We also thought that people might be worried about having to write profound observations on deep issues.  Don't.  Say what you think, and we'll talk about it - the good thing about a blog is that you can keep amending your threads.  As a good friend of mine said "Dobbiamo dialogare per non morire"  (We have to have dialogue, so we don't die!!).  This long prelude is merely to say that if you are uninspired by the stuff we bring up, ignore it, and write something yourself. 
 
I recently heard some comments from Jaroslav Pelikan a Yale theologian/historian.  He recently wrote a book about the history and influence of creeds in Christianity.  Pelikan believes that  "A creed is used to test the authority of what one is saying...[it is] a flag, an identity by which we are known by those who aren't a part of our community, but want to know what you are."  He sees creeds also as a uniting factor in space and time through which believers across centuries and separated by oceans can connect and relate.  On the other hand, Pelikan also sees creeds as stifiling and sometimes misguided. 
I have two questions, one general, one specific.  First, why has Christianity given itself so completely to the importance of creeds when the other two  monotheistic religions Judiasm and Islam have stayed away from them? (except maybe for the one basic creed "there is no god but Allah...")  Second,  given Pelikans definition of a creed as a flag, or a test for authority/authenticity how does mormonism's lack of formal creeds fit with that?  Do we have informal creeds that fulfill the same purpose?  Or is it that for mormons, like for jews and muslims, what we do is the important thing, not what we believe?