When you are offline and someone buffs your building(s) a note appears in your mailbox advising which building(s) where buffed, what they used and the person who applied the buffs. Is it possible for the same thing to happen when you are online? I'm sure a lot of people like me, have their pc's switched on and logged in to Settlers but don't religiously sit there all the time and so miss the friend who applies the buffs.