BobRay has pointed out in
one of his blog posts that the Articles templates uses the "username" placeholder in a few places. This is not a good idea, since this username is half of your Manager login. It makes a hacker's job that much easier when he already knows your username and can focus on trying to guess the password.
Articles uses getResources, so the same consideration would apply to any use of getResources where the author of the post is displayed. For example, in the getResources rtfm example, it's used:
<p class="author"><strong>Author:</strong> <span class="author">[[+createdby:userinfo=`username`]]</span></p>
http://rtfm.modx.com/display/ADDON/getResources#getResources-UsinggetPageforPagination
As Bob points out in his blog post, much better to use "fullname", thus not handing out to the hackers half of your Manager login.