Spread spectrum clock generator

[likephysics]

I was reading an article on spread spectrum clock generator here - http://www.maxim-ic.com/app-notes/index.mvp/id/1995
Wouldn't spreading the frequency from the center frequency affect the data transfer?
In case of a CPU, the speed would vary too.
I understand spread spectrum in communication, but I'm having a hard time convincing myself this would work in digital circuits.
Isn't this somewhat equivalent to jitter?

 

[Mike_In_Plano]

Usually, the system clock is fluctuated, and all the peices of the system run off the same clock. Therefore, they're all synched and the clock jumps about enough that the test facility gets a lower reading when performing interference tests.
The emission power is the same, it's just spread about so that less shows up within any narrow bandwidth.