I wasn't sure whether to try some airy description of the concept and what it might mean (I might have got away with that at a technology art conference, but the question and the context seemed to deserve a better answer), or let Pete chip in with something about the technical nuts and bolts.

We talked to Stuart Nolan about this afterwards, and after a while we came up with the line "It lets you get and add comments about the place you're in."

That seemed good enough, except that there is something about the word comment that sounds a bit one-off, not very active, and even a bit knit picking.

I thought it might be worth adding -tary.

Commentary makes me think both of a commentary to a book - extra information, useful facts, clarifications - and also the sports commentator, "they think it's all over" kind of exclamation, lasting for a period of time during an event. Those senses of commentary fit with some of the many ways people like to use their mobile phones.

Maybe that's what it is, a kind of two way (or many way) ongoing commentary organised around places. Maybe.

Note to self. Never put pun in title without checking spelling first.