Remember return receipts? Those annoying popups in your email that said, "So-and-so has asked to be notified when you read this message." Maybe you still use them (yikes). Boomerang however, takes an unobtrusive approach. It returns an email to your inbox if you do not receive a reply within a specific time.
Their "Send Later" feature is nice too. It's great for writing email now, and well.... sending it later :)
I've been using Boomerang for GMail for several months and I recommend it to anyone in the real estate business. They have a free version, so give it a try.
