On all of the launch videos and recordings for the Space Shuttle, the mention is made from Houston (after getting through Max-Q) of "go at throttle up", indicating that the launch is ok for going back to full thrust. Is there something that the astronauts on the shuttle needed to do manually at this point, or is this just courtesy information from the ground to let the on-board astronauts know what's going on (similar to other information from the ground later in the launch in regards to being able to make it to orbit if an engine fails, etc.)?
I'd always been under the impression that for launch that the astronauts were pretty much just along for the ride and computers controlled everything in regards to controls and actions until at least the main tank is released (assuming there are no issues). So, I'm curious the purpose of this instruction from the ground.