This sceencast explains the publish status feature in MediaDrop.

Initially all videos uploaded through the front-end or admin panel are placed under "awaiting review" status. Once the administrator hits the "review complete" button, they can upload media. Videos can be added in any format, however, they can only be published if they are in a web-ready format such as FLV, M4V, MP3, or MP4. Alternatively, if they are published through Youtube or Vimeo the encoding step is skipped

Once uploaded and encoded the administrator can then publish the video.