Continuing the discussion from "Off-topic" flag:
In the linked conversation we found that Discourse allows you to mark posts as off topic, but not whole topics. You can work around this by flagging the top post as off topic, but it would be easier for our moderators if this option was available on the topic level as well.
We have not yet researched whether this is planned for up-stream ( http://meta.discourse.org ). If someone wants to check that out for us before we get a chance to, that’d be great.