crowdfavorite/wp-social — comment on commit de91e57afeb56e3d11364f879aca941d9425b2fc
File: social.php line 507
By ziz:

It is equivalent here to pass a string or a variable containing a string; __ is a function (`function __( $text, $domain = 'default' )`, from wp-includes/l10n.php). You couldn't, for instance, pass a string with a php variable name in it (`__('$output')`), but there is nothing (technically) wrong with this usage.