title: NormalizedUserName VS Username in DotNet Core
body: <p>I'm trying to create a custom implementation of IUserLoginStore for MongoDB and I noticed when using </p>
  
  <pre><code>UserManager&lt;ApplicationUser&gt;
  </code></pre>
  
  <p>with the method</p>
  
  <pre><code> var userResult = await _userManager.CreateAsync(user);
  </code></pre>
  
  <p>it goes through the implementation of </p>
  
  <pre><code>GetUserNameAsync
  FindByNameAsync
  SetNormalizedUserNameAsync
  GetUserIdAsync
  </code></pre>
  
  <p>I would like to clarify two questions:</p>
  
  <ul>
  <li><p>what's the purpose of having a NormalizedUsername and a UserName? 
  the only difference that I could notice id that the normalizedUserName is in uppercase.</p></li>
  <li><p>I'm using my Implementation only to store users from an external login(Google plus), is there a way that I can omit username and NormilizedUserName since basically, I'm using the email in these three fields, I'm feeling that  I'm duplicating data and it doesn't make any sense to me.</p></li>
  </ul>
  
  <p>any recommendations?</p>