What does the Arrow Mean?

More on physical meets virtual with Yellow Arrow as featured on Gizmodo.

You get your little Yellow Arrows (see pic), each of which has a unique number on it. You put the Yellow Arrow somewhere visible in the real world, compose a text message about that place, then SMS it to Yellow Arrow, the organisation. The SMS for the pic here reads:

A horse dreams of an unpaved pasture. It remembers a life on the merry go round. Its music doesn't play anymore, laughter does.

People then see the arrow, text the unique number in and get back the message. Or they can do the same thing online.

It seems to be a social experiment rather than a commercial venture, as they say gnomically

The YellowArrow is an ongoing experiment; we want to hear your comments, questions, difficulties, ideas.