Poke is a messenger app, using icons instead of text. Originally conceived as a doorbell replacement, Poke can keep quick 'conversations' between people.
Currently the interface is rather bare-bones, but the technology is functional. People need to request permission to be able to send messages to others, in order to prevent spam. If person A wants to be able to 'poke' person B, person B will get a notice and has to approve the request. Person A and B are then both able to send messages to eachother.
Messages consist of an icon, a short title, and possible a sound. For instance the doorbell poke would also play the sound of a classic doorbell, since there would be a sense of urgency.
Poke runs on a python backend, hosted on Google App Engine. This server keeps track of the different device IDs registered per user.