allow private mail sender to set an expiration on their messages. Once expired the message is destroyed at both ends (subject to the granularity of the polling interval) and is gone. Officially it takes some form of language independent string like 2013/11/22, but English speakers can use anything that strtotime() understands, like "+30 minutes" or "next Tuesday".

include/poller.php

@@ -42,6 +42,11 @@ function poller_run($argv, $argc){
 		intval(ACCOUNT_EXPIRED),
 		intval(ACCOUNT_EXPIRED)
 	);
+
+	// expire any expired mail
+
+	q("delete from mail where expires != '0000-00-00 00:00:00' and expires < UTC_TIMESTAMP() ");
+	
   
 	// Ensure that every channel pings a directory server once a month. This way we can discover
 	// channels and sites that quietly vanished and prevent the directory from accumulating stale