Despite all the great user interface design we see on web applications today, one of the most important user interfaces for a SaaS product doesn’t live in the browser and may have very little “design” to it at all. It’s email. Yes, email! That bothersome bit of technology we all were expecting to die years ago is far from going off the deep end. Email is still the most important integration point for any web application. Here's 5 tips you must follow to integrate email to your product.