Programmatic buying uses software to buy advertising space that will get your adverts in front of the people who are most likely to click on them. Facebook’s Post Boost and Ads are examples of programmatic buying - you can choose an audience by demographic, interests, and location. Programmatic buying can serve your adverts to prospective clients on smaller websites that you might not be aware of. This is both its great strength and the point at which it can all fall apart.

The benefit of having your adverts appear on sites you’re not familiar with should be obvious. So long as you know who your customers are you can talk to them even if you don’t know what sites they are visiting. Instead of targeting ‘Mail & Guardian’ readers you can address people who visit any one of a number of similar sites, providing more granular targeting at relatively little expense.

The drawbacks attendant to this may be less obvious. A number of recent consumer campaigns have brought to light the way in which programmatic advertising can lead to companies advertising on outlets which may be harmful to their brand.

Recently big-name advertisers including Johnson & Johnson, The Guardian, and Coca-Cola discovered that their adverts were being displayed on jihadi and neo-Nazi YouTube pages and websites, as well as other disturbing content. While large corporations such as Coca-Cola are largely resistant to this kind of reputational contagion, smaller brands may not be. Terrorist atrocities aside, you probably don't want adverts for your eco-safari company running next to stories about a hunter being killed by wildlife in a nature reserve.

The other drawback is that much of the space sold using programmatic advertising is on the so-called ‘long tail’ of the internet - the vast number of sites which get small numbers of pageviews. Not only does indiscriminate programmatic advertising open your brand up to reputational harms, it can also be a huge waste of money.

American bank JP Morgan Chase, in response to the above-mentioned incidents, carried out a review of their online advertising. As a result, the bank reduced the number of websites it advertised on from around 400 000 sites to about 5 000 sites pre-approved by the company.

Despite reducing the number of sites the bank advertised on by 98%, they saw no significant decline in their advertising performance metrics. This was because they were receiving clicks from less than 3% of the sites they were advertising on. Once the bank had culled the non-performing sites and carried out a review of the performing sites for suitability they were left with a much smaller whitelist of sites.

While it may be tempting to click a few buttons on a dashboard and let the algorithms get on with it these cases show that it is essential not to treat programmatic advertising as an automatic process that can run in the background. Monitoring where your adverts appear and how they perform will not only save you money; it can also save your reputation.