Site-wide 'online now' as in forums
Using Jamroom
Use the jrUser_whos_online function.
{jrUser_whos_online template="whos_online.tpl"}
whos_online.tpl
{if isset($master)}
Master Admins
{foreach from=$master item="m_admin"}
<a href="{$jamroom_url}">{jrCore_module_function function="jrImage_display" module="jrUser" type="user_image" item_id=$m_admin.session_user_id size="xsmall" crop="auto" class="iloutline" alt=$m_admin.session_user_name title=$m_admin.session_user_name}</a><br><br>
{/foreach}
{/if}
{if isset($admin)}
Site Admins<br>
{foreach from=$admin item="s_admin"}
<a href="{$jamroom_url}/{$s_admin.profile_url}">{jrCore_module_function function="jrImage_display" module="jrUser" type="user_image" item_id=$s_admin.session_user_id size="xsmall" crop="auto" class="iloutline" alt=$s_admin.session_user_name title=$s_admin.session_user_name}</a><br><br>
{/foreach}
{/if}
{if isset($user)}
Members<br>
{foreach from=$user item="member"}
<a href="{$jamroom_url}/{$member.profile_url}">{jrCore_module_function function="jrImage_display" module="jrUser" type="user_image" item_id=$member.session_user_id size="xsmall" crop="auto" class="iloutline" alt=$member.session_user_name title=$member.session_user_name}</a><br><br>
{/foreach}
{/if}
<hr>
Master Admins: {$master_count}<br>
Site Admins: {$admin_count}<br>
Members: {$user_count}<br>
Visitors: {$visitor_count}<br>
Total: {$all_count}