The immature digital ad market has to determine what it values and why

I want to sell you a poster (unusual, for someone who works for a newsbrand).
Here's one: It's nice. It's part of a bus stop. People will hang around it, may well consume your message. It's quite small though and there are loads of them, all the way down the road.
Here's another: It's a giant. It's beautifully lit, looks elegant and impactful. It's on the North Circular so there are always queues. It will get noticed so there's a good chance it will be effective. It’s great for brands.
If