Throngs of people have been milling seemingly aimlessly around the forecourt of a museum in central Seoul, brushing silently past each other with heads bent toward smartphones while fingers frantically tap screens — in the latest money-making trend.

Walking 10,000 steps, completing tasks such as subscribing to social media, or just tapping the screen when other users are nearby can generate up to 10 cents a time for users of financial services app Toss from South Korean startup Viva Republic.

The viral campaign has seen Toss become a front-runner in a trend where businesses win users through cash- and points-offering loyalty apps, which have risen in popularity in an economy with high youth unemployment and surging inflation.