Imagine if your exercise tracking app could also tell when you looked tired after a run. Or if the online class you were taking could flag the teacher when you looked confused. Today, websites and apps already track our every click and scroll. Soon they could be tracking our emotions, too.

Affectiva, founded in 2009 out of MIT’s Media Lab, is a startup that has made its name over the last few years with its emotion-tracking technology that analyzes people’s facial expressions through the camera on their computer. Its long-term goal is to be the “emotion data layer” between consumers and their ever-multiplying apps and devices, says Affectiva CEO Nick Langeveld.

There’s an emotional layer that really sits in between the consumer and those devices.

So far, the company’s main product, Affdex, has primarily been used in the most obvious application from a business standpoint: by advertisers, market researchers, and brand developers seeking to measure reactions to products or messaging.

More recently, however, with the recent release of a mobile software developer kit, Affectiva has been courting customers in other sectors, including health, education, and gaming apps.

Take education: “Online education has a long way to go,” says Affectiva CEO Nick Langeveld. “One of the ways it could become more useable is by having an ability for the instructor to understand the pupils–just as they would in a normal classroom environment. Are they laughing at my jokes? Do they get it?”

It’s not just teachers that may find emotion-tracking. Soon, everyone from doctors to game designers may find uses in better understanding people’s levels of boredom, stress, or engagement as they watch a video or move through a storyline in a game–not to mention individuals themselves interested in the “quantified-self” movement. “We look at the consumer in the middle and all of these different digital experiences around that consumer. In reality, there’s an emotional layer that really sits in between the consumer and those devices and those experiences,” says Langeveld.

So far, Affectiva is just starting to have discussions with these kinds of developers, and Affectiva isn’t the only company devising new strategies to track people’s emotional reactions while carrying or using devices. Langeveld imagines some additional R&D could be needed to adapt its emotion coding schemes to different sectors.