Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

http://home.trainingpeaks.com/land/what-is-tss.aspx

At it's most basic, 1 hour at threshold is 100 TSS points, is my understanding- hence when I managed to score over 100 TSS/hour it attracted some derision.

As that should be impossible.

It's not impossible, it's unlikely - you could have a breakthrough workout or say have your FTP incorrectly calculated :)