The Financial Times thinks we

The Financial Times thinks we may have something similar to the Marauder’s Map soon:

Some of the services mooted by mobile phone operators will place little digital maps on handsets that will alert users to the proximity of any fellow mobile phone users whose names are in our address books. Like Harry Potter looking at his map of Hogwart’s School, we will be able to see little blobs winking on the map where our friends are.