Cottonbro Studio/Pexels, CC BYIt’s Saturday night and you’ve downloaded a new food delivery app. You’ve scanned the menus, picked some Mexican dishes, placed your order and are now tracking the delivery. But your food never comes – and you never expected it to.It sounds ridiculous if you’ve never tried it, but this viral trend is more popular than you might think. Just one app alone, FoodNeverComes, claims nearly 1 million “cravings satisfied” to date.Why would people bother spending time on apps or websites that are built to never deliver? Ultimately, it’s all about getting a dopamine hit.It sounds like harmless fun, letting users “buy” food, clothes or other products with no real-world cost, since most of these apps are free to use. But even when an app or website costs you nothing, there are downsides to watch out for – including how your choices can help advertisers better target you in real life.From South Korea to the worldFoodNeverComes is one example of a free, ad-supported app and website that mimics an online food delivery service. But there are other types too. For instance, the free, ad-supported Dopamine Shop is a fake online shopping site. There, customers view items – everything from a 99 cent pet rock to a $99 million moon – then fill their carts. But no payment details are requested and no transaction ever occurs. Nothing is ever shipped.There are even fake, free “smoking” apps such as No Smoke Zone, also known as Virtual Smoke, which describes itself like this:Virtual Smoke is a realistic cigarette simulation app that lets you enjoy the look, feel, and relaxation of smoking – without any nicotine or harmful effects. Perfect for those trying to quit, reduce stress, or just have fun with a virtual cigarette.These new platforms are what’s known as “dopamine apps” or “dopamine sites”.While they began in South Korea, interestingly, Dopamine Shop is owned and developed by Fenwick Holdings LLC, a small independent studio in the United States. This suggests this new genre of apps and websites may be spreading globally.Why does it feel so good?Dopamine is both a powerful neurotransmitter and neuromodulator – delivering chemical messages and sparking changes in your brain.Dopamine plays several important roles, including motivating us toward goals and helping your brain learn which actions lead to beneficial outcomes. With these new dopamine platforms, users experience:anticipation (“I might find something good”)selection (“I control my choices”)and a feeling of confirmation (“My order is placed!”).The only element of the process missing, compared to a real app or website, is consumption (“I received it”).Even before these latest apps, some people had already realised they can get a similar retail therapy rush by creating wish lists or filling their cart, then deleting it, without making a purchase.You can simulate the same feeling by creating Pinterest boards of your dream home, without building a thing. Or you can imagine your dream holiday, using various free or paid travel planning apps and websites.Potential as a ‘gateway behaviour’Could pretending to order food, shopping or having “fun with a virtual cigarette” have any downsides?These dopamine apps and websites are relatively new, so we don’t yet have specific research on how much, if at all, they might serve as “gateway behaviours”. A gateway behaviour is an initial behaviour that opens a pathway toward later behaviours becoming more likely.However, this is an area that’s been well studied before in other areas, such as gambling and gaming. And that past research raises potential concerns – particularly since these dopamine apps involve some level of gamification. For example, a notable 2014 study followed 409 people who played social casino games, but who had never gambled online with real money. Six months later, about 26% had migrated to real online gambling.A 2016 study of 521 social casino users found 19% reported gambling for real money as a direct result of social casino gaming.And a 2018 study of 1,178 German teens, aged 11 to 19, found that engagement with simulated gambling predicted subsequent real money gambling one year later.How your ‘cookies’ feed targeted adsRemember the old saying, “there’s no such thing as a free lunch”?While these apps and websites might be fun and free, your fake choices can still be incredibly valuable for marketers.Free apps often rely on advertising to pay for making their content free. Apps or websites that use Google AdSense to display their ads use cookies: tiny text files stored on your browser to track your online browsing habits. Third-party advertisers, including Google, can then use your history to serve you more targeted ads. (If you read the fine print, sites note how to opt out of personalised advertising.)If you do purchase that pretend jacket, or order that delivery of fake tacos, don’t be surprised if you start seeing more ads for the real thing.Gary Mortimer has received past funding from the Building Employer Confidence and Inclusion in Disability Grant, the AusIndustry Entrepreneurs' Program, the National Clothing Textiles Stewardship Scheme, the National Retail Association and the Australian Retailers Association. He is an independent director and board chair of Services and Creative Skills Australia, a federally-funded jobs and skills council.