I get this question a lot. As if there is some magic algorithm I can pull up that will pin down the exact day and time to send customer's email. I've been on teams that test, test, test to pinpoint the day and I have been on teams that just wing it. What is the outcome? Both see comparable open rates, click-through rates, and conversions.

My simple answer? Let the web traffic tell you. If my traffic tends to slip on Thursdays and Fridays, I am darn sure to send an email at the tail end of the week.