A surprising thing happened when Procter & Gamble, the consumer goods giant behind Gillette razors, Crest toothpaste and Pampers nappies, trimmed $100m from its digital marketing costs in the second quarter: nothing changed.

“We didn’t see a reduction in the growth rate [in value or volume of sales],” Jon Moeller, P&G’s chief financial officer, told investors. “What that tells me is that the spending that we cut was largely ineffective.”

P&G’s cuts were aimed at websites where its ads were more likely to be viewed by bots, computer programs that simulate the activity of real people browsing the web, and those where its brands were appearing next to undesirable content. “We want our advertising to be seen by real people,” a spokesperson said.