South Africa, May 25 -- There's a reason marketers have spent the last decade pouring budget into digital advertising. It's not just that digital reaches people - it's that digital tells you exactly what happened afterwards. The click. The conversion. The online sale. Every action logged, timestamped, attributed.

The problem is that this level of information has created data blindness. Dashboards full of impressions, bounce rates, CPMs and click-through rates that tell you a lot - and somehow still leave you unsure whether any of it actually moved anyone into a store or to a website.

Meanwhile, the billboard on the highway has been quietly doing its job. Brands just couldn't really prove it.

Vicinity Media's Omnichannel Analytics meas...