This is very old - firebox.com started in 1998 and went on to become the 13th fastest growing privately owned UK company in 2004 when they achieved annual sales of £4.4 million and 150% pa growth (www.fasttrack.co.uk).
I don't understand, don't they do load testing and profile their own code? How hard can it be to setup a single dummy server instance on some cloud computing platform and just monitor its performance as they stress test it?