If database space is a problem, may I suggest you make it a client-side setting and store the list of ignored users somewhere in the users' settings directories? While that would still clear the ignore-list upon reinstall of the client, at the very least it won't clear it every single time you log-out, which is already much better. You don't even need to really implement client-side chat filtering in any way if it's currently done server-side -- just have the client spam /ignore for each player in this list when it logs in. The list will still be cleared on the server when you log out, but re-created when you log back in again, so it's essentially permanent. Alternatively, implement a limit -- up to, say, 100 blocked users for each account. Or even do both.