Kano Model

The Kano model is a theory for product development and customer satisfaction developed in the 1980s by Professor Noriaki Kano, which classifies customer preferences into five categories. Wikipedia

Kano Curve, from Wikipedia.

You can use this model to figure out what it's best to invest in for a project. If a feature is relatively novel then people tend to really like it and it helps a product stick. However, if a feature is expected or something that people don't really care about, then it's going to need to be good, but not great.

This kind of reminds me of the "If you're great, you don't have to be good" blogpost from one of the devs on the gmail team. I can't find this at the moment, but it's that kind of thing that can help you stand out.