Simply put Aurasma allows you to overlay a video over an image. When someone using the app views that image then the video is activated.
The app is easy to use, first you record the video then you choose an image to put it on and that it's it. You can either record and take the videos via the app or use ones previously made. The ease of use is a definitely a bonus for the ELT classroom as there are few complicated instructions that need to be conveyed.
At BETT, the uses of it that caught my eye were to do with bringing written work to life. One immediate cross over is that of book reviews. Many ELT classrooms use graded readers with teachers setting the dreaded written book review once the students have done. Using Aurasma, the student instead could record their review and overlay that on the cover of the book. Fellow students can then use the app cover to see what their peers thought of the book. Alternatively the covers of the book (or other illustration) can be put around the classroom wall and the app used that way.
Using the app to bring the walls to life can lead to more clever adaptations of activities. In many classrooms, students work is put on the wall. Using Aurasma, the author or the work can record a video to accompany and add further details; activated when the reader waves the app over the work.
Furthermore the app could be used to bring vocabulary to life. Vocabulary is often put around the walls of the ELT classroom, well if you overlay a photo rather than a video you can do things such as overlay translations, contextualising sentences and so on. Alternatively use the video option to add the pronunciation.
It seems to me there is a growing interest in augmented reality and the aurasma app is an easy way to introduce this in to the ELT classroom.