Does anyone know about what app, what does this mean.. Watch
Not necessarily, as they may have a weak Internet connection, and if you are added to a group chat you will not see any messages beforehand. If all members could see teh message it'd be two grey ticks, if they all see it it's two blue ticks. (1 blue tick means at least someone has seen it other than you). I think if you hold down on the message you sent you can see who saw it and when /when it was delivered.