Index: bp-core/bp-core-filters.php
===================================================================
--- bp-core/bp-core-filters.php	(revision 7373)
+++ bp-core/bp-core-filters.php	(working copy)
@@ -253,7 +253,7 @@
 		$admin_email = 'support@' . $_SERVER['SERVER_NAME'];
 
 	$from_name       = bp_get_option( 'blogname', 'WordPress' );
-	$message_headers = "MIME-Version: 1.0\n" . "From: \"{$from_name}\" <{$admin_email}>\n" . "Content-Type: text/plain; charset=\"" . get_option( 'blog_charset' ) . "\"\n";
+	$message_headers = "MIME-Version: 1.0\n" . "From: \"{$from_name}\" <{$admin_email}>\n" . "Content-Type: text/plain; charset=\"" . get_option( 'blog_charset' ) . "\"\n" . "Auto-Submitted: auto-generated\n";
 	$message         = sprintf( __( "Thanks for registering! To complete the activation of your account and blog, please click the following link:\n\n%1\$s\n\n\n\nAfter you activate, you can visit your blog here:\n\n%2\$s", 'buddypress' ), $activate_url, esc_url( "http://{$domain}{$path}" ) );
 	$subject         = bp_get_email_subject( array( 'text' => sprintf( __( 'Activate %s', 'buddypress' ), 'http://' . $domain . $path ) ) );
 
@@ -281,7 +281,7 @@
 		$admin_email = 'support@' . $_SERVER['SERVER_NAME'];
 
 	$from_name       = bp_get_option( 'blogname', 'WordPress' );
-	$message_headers = "MIME-Version: 1.0\n" . "From: \"{$from_name}\" <{$admin_email}>\n" . "Content-Type: text/plain; charset=\"" . get_option( 'blog_charset' ) . "\"\n";
+	$message_headers = "MIME-Version: 1.0\n" . "From: \"{$from_name}\" <{$admin_email}>\n" . "Content-Type: text/plain; charset=\"" . get_option( 'blog_charset' ) . "\"\n" . "Auto-Submitted: auto-generated\n";
 	$message         = sprintf( __( "Thanks for registering! To complete the activation of your account please click the following link:\n\n%1\$s\n\n", 'buddypress' ), $activate_url );
 	$subject         = bp_get_email_subject( array( 'text' => __( 'Activate Your Account', 'buddypress' ) ) );
 
Index: bp-core/deprecated/1.5.php
===================================================================
--- bp-core/deprecated/1.5.php	(revision 7373)
+++ bp-core/deprecated/1.5.php	(working copy)
@@ -367,8 +367,9 @@
 			$to = apply_filters( 'groups_at_message_notification_to', $to );
 			$subject = apply_filters( 'groups_at_message_notification_subject', $subject, $group, $poster_name );
 			$message = apply_filters( 'groups_at_message_notification_message', $message, $group, $poster_name, $content, $message_link, $settings_link );
+			$message_headers = "Auto-Submitted: auto-generated\n";
 
-			wp_mail( $to, $subject, $message );
+			wp_mail( $to, $subject, $message, $message_headers );
 		}
 	}
 
Index: bp-friends/bp-friends-notifications.php
===================================================================
--- bp-friends/bp-friends-notifications.php	(revision 7373)
+++ bp-friends/bp-friends-notifications.php	(working copy)
@@ -48,8 +48,9 @@
 	$to = apply_filters( 'friends_notification_new_request_to', $to );
 	$subject = apply_filters( 'friends_notification_new_request_subject', $subject, $initiator_name );
 	$message = apply_filters( 'friends_notification_new_request_message', $message, $initiator_name, $initiator_link, $all_requests_link, $settings_link );
+	$message_headers = "Auto-Submitted: auto-generated\n";
 
-	wp_mail( $to, $subject, $message );
+	wp_mail( $to, $subject, $message, $message_headers );
 
 	do_action( 'bp_friends_sent_request_email', $friend_id, $subject, $message, $friendship_id, $initiator_id );
 }
@@ -86,8 +87,9 @@
 	$to = apply_filters( 'friends_notification_accepted_request_to', $to );
 	$subject = apply_filters( 'friends_notification_accepted_request_subject', $subject, $friend_name );
 	$message = apply_filters( 'friends_notification_accepted_request_message', $message, $friend_name, $friend_link, $settings_link );
+	$message_headers = "Auto-Submitted: auto-generated\n";
 
-	wp_mail( $to, $subject, $message );
+	wp_mail( $to, $subject, $message, $message_headers );
 
 	do_action( 'bp_friends_sent_accepted_email', $initiator_id, $subject, $message, $friendship_id, $friend_id );
 }
Index: bp-members/bp-members-functions.php
===================================================================
--- bp-members/bp-members-functions.php	(revision 7373)
+++ bp-members/bp-members-functions.php	(working copy)
@@ -1446,8 +1446,9 @@
 	$to      = apply_filters( 'bp_core_signup_send_validation_email_to',     $user_email, $user_id                );
 	$subject = apply_filters( 'bp_core_signup_send_validation_email_subject', $subject,    $user_id                );
 	$message = apply_filters( 'bp_core_signup_send_validation_email_message', $message,    $user_id, $activate_url );
+	$message_headers = "Auto-Submitted: auto-generated\n";
 
-	wp_mail( $to, $subject, $message );
+	wp_mail( $to, $subject, $message, $message_headers );
 
 	do_action( 'bp_core_sent_user_validation_email', $subject, $message, $user_id, $user_email, $key );
 }
Index: bp-activity/bp-activity-notifications.php
===================================================================
--- bp-activity/bp-activity-notifications.php	(revision 7373)
+++ bp-activity/bp-activity-notifications.php	(working copy)
@@ -104,8 +104,9 @@
 		$to 	 = apply_filters( 'bp_activity_at_message_notification_to', $to );
 		$subject = apply_filters( 'bp_activity_at_message_notification_subject', $subject, $poster_name );
 		$message = apply_filters( 'bp_activity_at_message_notification_message', $message, $poster_name, $content, $message_link, $settings_link );
+		$message_headers = "Auto-Submitted: auto-generated\n";
 
-		wp_mail( $to, $subject, $message );
+		wp_mail( $to, $subject, $message, $message_headers );
 	}
 
 	do_action( 'bp_activity_sent_mention_email', $activity, $subject, $message, $content );
@@ -182,8 +183,9 @@
 		$to = apply_filters( 'bp_activity_new_comment_notification_to', $to );
 		$subject = apply_filters( 'bp_activity_new_comment_notification_subject', $subject, $poster_name );
 		$message = apply_filters( 'bp_activity_new_comment_notification_message', $message, $poster_name, $content, $thread_link, $settings_link );
+		$message_headers = "Auto-Submitted: auto-generated\n";
 
-		wp_mail( $to, $subject, $message );
+		wp_mail( $to, $subject, $message, $message_headers );
 
 		do_action( 'bp_activity_sent_reply_to_update_email', $original_activity->user_id, $subject, $message, $comment_id, $commenter_id, $params );
 	}
Index: bp-messages/bp-messages-notifications.php
===================================================================
--- bp-messages/bp-messages-notifications.php	(revision 7373)
+++ bp-messages/bp-messages-notifications.php	(working copy)
@@ -70,8 +70,9 @@
 			$email_to      = apply_filters( 'messages_notification_new_message_to',      $email_to );
 			$email_subject = apply_filters( 'messages_notification_new_message_subject', $email_subject, $sender_name );
 			$email_content = apply_filters( 'messages_notification_new_message_message', $email_content, $sender_name, $subject, $content, $message_link, $settings_link );
+			$email_headers = "Auto-Submitted: auto-generated\n";
 
-			wp_mail( $email_to, $email_subject, $email_content );
+			wp_mail( $email_to, $email_subject, $email_content, $email_headers );
 		}
 	}
 
Index: bp-groups/bp-groups-notifications.php
===================================================================
--- bp-groups/bp-groups-notifications.php	(revision 7373)
+++ bp-groups/bp-groups-notifications.php	(working copy)
@@ -45,8 +45,9 @@
 		$to      = apply_filters( 'groups_notification_group_updated_to', $to );
 		$subject = apply_filters_ref_array( 'groups_notification_group_updated_subject', array( $subject, &$group ) );
 		$message = apply_filters_ref_array( 'groups_notification_group_updated_message', array( $message, &$group, $group_link, $settings_link ) );
+		$message_headers = "Auto-Submitted: auto-generated\n";
 
-		wp_mail( $to, $subject, $message );
+		wp_mail( $to, $subject, $message, $message_headers );
 
 		unset( $message, $to );
 	}
@@ -96,8 +97,9 @@
 	$to      = apply_filters( 'groups_notification_new_membership_request_to', $to );
 	$subject = apply_filters_ref_array( 'groups_notification_new_membership_request_subject', array( $subject, &$group ) );
 	$message = apply_filters_ref_array( 'groups_notification_new_membership_request_message', array( $message, &$group, $requesting_user_name, $profile_link, $group_requests, $settings_link ) );
+	$message_headers = "Auto-Submitted: auto-generated\n";
 
-	wp_mail( $to, $subject, $message );
+	wp_mail( $to, $subject, $message, $message_headers );
 
 	do_action( 'bp_groups_sent_membership_request_email', $admin_id, $subject, $message, $requesting_user_id, $group_id, $membership_id );
 }
@@ -154,8 +156,9 @@
 	$to      = apply_filters( 'groups_notification_membership_request_completed_to', $to );
 	$subject = apply_filters_ref_array( 'groups_notification_membership_request_completed_subject', array( $subject, &$group ) );
 	$message = apply_filters_ref_array( 'groups_notification_membership_request_completed_message', array( $message, &$group, $group_link, $settings_link ) );
+	$message_headers = "Auto-Submitted: auto-generated\n";
 
-	wp_mail( $to, $subject, $message );
+	wp_mail( $to, $subject, $message, $message_headers );
 
 	do_action( 'bp_groups_sent_membership_approved_email', $requesting_user_id, $subject, $message, $group_id );
 }
@@ -202,8 +205,9 @@
 	$to      = apply_filters( 'groups_notification_promoted_member_to', $to );
 	$subject = apply_filters_ref_array( 'groups_notification_promoted_member_subject', array( $subject, &$group ) );
 	$message = apply_filters_ref_array( 'groups_notification_promoted_member_message', array( $message, &$group, $promoted_to, $group_link, $settings_link ) );
+	$message_headers = "Auto-Submitted: auto-generated\n";
 
-	wp_mail( $to, $subject, $message );
+	wp_mail( $to, $subject, $message, $message_headers );
 
 	do_action( 'bp_groups_sent_promoted_email', $user_id, $subject, $message, $group_id );
 }
@@ -258,8 +262,9 @@
 		$to      = apply_filters( 'groups_notification_group_invites_to', $to );
 		$subject = apply_filters_ref_array( 'groups_notification_group_invites_subject', array( $subject, &$group ) );
 		$message = apply_filters_ref_array( 'groups_notification_group_invites_message', array( $message, &$group, $inviter_name, $inviter_link, $invites_link, $group_link, $settings_link ) );
+		$message_headers = "Auto-Submitted: auto-generated\n";
 
-		wp_mail( $to, $subject, $message );
+		wp_mail( $to, $subject, $message, $message_headers );
 
 		do_action( 'bp_groups_sent_invited_email', $invited_user_id, $subject, $message, $group );
 	}