BT Speedtester - "number of threads"

[#1]

When running the BT Speedtester, after the test has got half way through, I get a message underneath the top progress bar saying "The number of threads is 16!" Does anyone know what this means? I've looked in the Speedtester FAQ and there doesn't seem to be any explanation there.
The test (usually) completes normally, so it's not a problem, but I'm just curious. Does the exclamation mark mean the number of threads in my tests is unusual? Does anyone else see a different number?
Graham

[#2]

I get the same message every time I run the BT speedtestr and it always makes me smile - 16!
Would also be interested to know what this actually indicates. Could the exclamation mark mean factorial? I'm guessing probably not as 16! = 2.09227899 × 10¹³