Ask Ariely: On Gifting Gratitude and Requesting Reply – Dan Ariely:

I gave them a pull down menu with options that ranged from “drop everything and answer me now” to “by the end of the day” to “by the end of the week,” to “by the end of the month,” and I also added an option I was most curious about, which was “no response necessary.” It was surprising to me how many emails were in the “no response necessary” category (about 20%) and more surprising how few emails were in the “drop everything and answer me now” category (about 2%).

*Interesting idea. This test gave insights one may not know about.