Ideally: take a polaroid picture of each participant, and write some 'metadata' on it – the place the photo was taken, the time, and the kind of camera used to take the photo.
If facilitators can't get hold of a polaroid camera, then ask participants to bring in a photo of themselves to the session, that (ideally) they don't mind writing on and using for the session.
Once metadata has been put on the photos of participants, give them back to the participants, along with a big sheet of paper and glue, and ask participants to draw the different data shadows and traces that they leave, associated with devices and online services that they use.
If possible, provide people with a variety of art materials – glitter, coloured pens, stickers, etc, and encourage them to use anything they like to express and visualise their data shadows. express and visualise their data shadows.