Last time I was there, two of the four adverts shown in the time I was walking past were for the SA Tourism Commission, so it would appear to be having a modest level of success at bringing in private sector revenue.
It's a bit back to the future don't you think? There used to be a massive screen near the waiting area with the benches and vending machines before that area was removed to build the InfoCentre - and there was also space where people could wait there unlike today's layout of the station which actively encourages going directly to your train.
I think there's a chance they might have the effect of encouraging people to run for their train more often since the trains can't be seen so easily.
A couple of years ago, I read in a marketing-industry journal about a proposal to instal banks of big screen TVs above the checkouts in supermarkets.
These would be used to expose the captive audience to "messages" and, according to the article, supermarkets would be "encouraged" not to have their checkout lines too short or fast-moving, so as to maximise exposure time to the hapless punters.
This was just before the faster self-checkouts started to come in, so I'm glad the supermarkets never proceeded with it - yet.
Anyhow, to me, it seems a bit late to try to start selling stuff once the shopper is in the checkout queue (unless it's Kit-Kats or Tic-Tacs), but I guess some guru got a big consultancy fee for that idea.
I think that would have been incredibly effective. That time in the checkout queue is when people are already actively thinking about purchasing decisions, so there wouldn't be any better time to hit them with ads even for products not sold in supermarkets.
It would also be incredibly annoying, and in Australia it would be a big winner for independents and Aldi if one of the big two introduced it.
We used to call them (and I still do) Advertising Hoardings.
There are three major differences between a screen and a traditional poster or hoarding (of which there have always been plenty at ARS and on trains):
1. the space can be sold to multiple advertisers at once.
2. loading a new file into a playlist has no overheads.
3. movement catches the eye.