Problem with a lot of the serverhop ones, is that Blizz changed server groups so, you have to be in the same 'area' as the leader to get phased to their server.
it can be buggy sometimes, but you should be in the same location as group leader. New feature as "In moderation" it's just a latest update thing i suppose, just checkout mode author page
Since a few months ago , they changed the way this works, you can only server hop if there is a group of players with auto-accept invitation in the area you want to hop in. So basicly you can only use this service now in populated areas.