Customize the Post Info on a Genesis child theme in a multisite environment for a specific blog.

multisite-custom-post-info.php

<?php 
/**
 *
 * Customize Post Info on a specific multi-site blog
 *
 * http://wordpress.org/support/topic/how-to-get-current-site-blog-id?replies=9#post-1610948
 * http://my.studiopress.com/snippets/post-info/#customize
 */

add_filter( 'genesis_post_info', 'post_info_filter' );
function post_info_filter( $post_info ) {
  global $blog_id;
  if ( 1 == $blog_id ) {
    $post_info = 'by [post_author_posts_link] [post_comments] [post_edit]';
  } else {
    $post_info = '[post_date] by [post_author_posts_link] [post_comments] [post_edit]';
  }
  return $post_info;
}