the "forumhome_loggedinuser" template should be
HTML Code:
<if condition="$show['comma_leader']">, </if>$stylevar[dirmark]<a href="member.php?$session[sessionurl]u=$loggedin[userid]">$loggedin[musername]</a>$loggedin[invisiblemark]<if condition="$loggedin[buddymark]"><img src="/images/statusicon/buddy.gif" alt="User is on your buddy list"></if>
for it to give you the comma inbetween each username.
Tested and working on vb3.7.3