Voir ici :
http://wpchannel.com/supprimer-blog-permaliens-wordpress-3-0-multisite/
Function.php
add_filter("pre_update_option_category_base","cc_remove_blog_slug"); add_filter("pre_update_option_tag_base","cc_remove_blog_slug"); add_filter("pre_update_option_permalink_structure","cc_remove_blog_slug"); function cc_remove_blog_slug($tag_cat_permalink){ if(!preg_match("/^\/blog\//",$tag_cat_permalink)) return $tag_cat_permalink; $new_permalink=preg_replace ("/^\/blog\//","/",$tag_cat_permalink ); return $new_permalink; }