User blog comment:Blackbird625/What does this mean?/@comment-27403314-20140906193204

That can be modified at MediaWiki:Wikia.css, which the code is:

a[href="/wiki/User:Blackbird625"] {color:#0099FF !important; font-weight:bold;}

The 'color:#0099FF' part is what changes the font color of your username. The same applies to anyone else with a different font color username compared to normal users. :)