...Nicely reflected not only in the Livejournal thread linked to in the original post, but in the string of alerts from the T, as archived at wheresthet.com:

6:31 a.m.
Blue Line experiencing 15-20 min delays due to disabled train at Aquarium

7:01 a.m.
Blue Line: is being diverted due to disabled train at Aquarium. A bus shuttle will accommodate customers between Maverick and Government Center. Significant delays in both directions. Seek alternate transportation to avoid delay.

7:11 a.m.
Due to Power Problem at Aquarium Station (Blue Line) please use Silver Line service into South Station

7:31 a.m.
Blue Line: is being diverted due to disabled train at Aquarium. A bus shuttle will accommodate customers between Airport and Government Center. Significant delays in both directions. Seek alternate transportation to avoid delay.

7:51 a.m.
Due to Power Problem at Aquarium Station (Blue Line) please use Silver Line service between Airport and South Station.

It's a sign of how major the disruption was that alerts also went out tagged for users of the Red, Green, and Orange lines!

Fabulously Out There had her camera with her yesterday:

It was actually rather civil until people from the back started running toward the buses in the front and mistaking Terminal buses for real buses. I am telling you, it felt like what it must have felt like standing in line for freaking bread in Communist Russia.

Since the "Silver Line" doesn't actually exist, the T can put it anywhere they want.