About Email Frequecy

Hello Friends,

I am a bit confused with regard to the Email Frequency/communication limit set up in Marketo. I know its under the Admin control, but would like to understand what exactly are the Email cycle parameters?

Is it Per 7 days or Per 5 business days?

And for either of the 2 above parameters, is it counted from the last email sent or counted from the starting of the week?

Thanks,

Debroop.