Despite the fact that email is still the most broadly used form of digital communication, it sometimes gets a bad rap and is often proclaimed outdated and on the brink of being replaced by more progressive communication technologies.
However, email is simple and everyone uses it, all the time. That is why email still represents a huge opportunity for innovations in the architectures of web applications. Given the popularity of email, you can even argue that it is heavily underutilised in this regard.
A great example of how email can enrich the user experience of a web application is TripIt. TripIt is a social networking site for travellers that organises your travel plans and alerts you when you are near friends and colleagues. The killer feature is in the way you set up a new trip on your profile. All you have to do is forward your travel itinerary via email and TripIt takes care of the rest.
That is a great example of how email can be used to simplify and enrich the user experience. And it gives TripIt an effective way of signing people up because initially all you have to do is emailing them your itinerary, very easy.