The method of handling @mentions with Twitter appears to be very poor.

Receive an @mention it only appears in the @Mentions column under Monitor. If we then reply there is no way to track if an @mention has been replied to or not.

There must be a way to see all @mentions with no response. Need to be able to mark @mentions as viewed or replied to so that agents do not reply multiple times to the same @mention.

Facebook visitor posts at least show that a response has been made with number of replies in the conversation. But again the ability to archive these unless a new response is received would help.