Have you ever ploughed through page after page of an airline booking site, only to find you had paid for a whole lot of stuff you didn't want – checked baggage allowance, insurance, or an allocated seat, for instance? Or have you downloaded some new software and found a mysterious new toolbar on your browser, additional software on your desktop or a new default search engine?

In all likelihood you actually agreed to get these things – you just didn't realise it, because it was done in a sneaky way. And there's a name for these sneaky tricks: dark patterns.

Take a walk on the dark side

The term "dark patterns" was coined by Dr Harry Brignull, a UK-based consultant on website user experience design. He explains that while the user interfaces on some websites are just badly designed and poorly thought through, others are deliberately designed to mislead.

The people behind these tricks benefit in several ways, including income through:

  • "pay per click" (where payment is received each time someone clicks on an ad)
  • signing people up to subscriptions
  • obtaining personal information or information about friends
  • getting access to people's computers
  • getting people to buy things they don't want.

Ticket to rort

If you've ever booked a flight online, you'll know all about "sneak into basket" dark patterns. These are the little checkboxes already pre-ticked on your behalf, which sneak little extras into your shopping basket – baggage, insurances, seats and so on. If you don't want them, you have to manually opt out by un-ticking the box.

Our very own Jetstar has achieved such notoriety for its add-ons that it's cited internationally as a model of this consumer dark pattern trap. As an example, when CHOICE logged on to book one return flight from Sydney to Melbourne, the following items were pre-selected for our convenience:

  • 20kg baggage – $16.50 per flight.
  • Seats – $5 per flight. If we chose not to have preselected seats, we would have a seat randomly allocated to us. However, reading the fine print, we found there's actually no guarantee we would even get the seat we paid for. So exactly why did we pay for them to allocate us a seat? We could, in fact, skip this step and have a free seat randomly allocated to us by clicking the very small "skip seat selection" link under the "Continue" button.
  • Insurance – $12.95
  • A donation to StarKids charity – $2.

These "conveniences" brought our $170 fare to $227.95 – and that's before Jetstar added the $17 credit card surcharge. Other options on offer included carbon offsets, an SMS itinerary and a package providing more fare flexibility – these were not pre-selected, so we had to opt in if we wanted them.

Apart from being a great example of drip pricing – the practice (which the ACCC is cracking down on) of adding lots of small charges to the initial advertised price, including pre-selected or opt-out inclusions – there are several other dark patterns at play. The pre-selected options require extra vigilance to uncheck them, as does the relatively small opt-out text for seat selection. Convenient? Not really.

Meanwhile, for the convenience of EU consumers, Consumer Directive Memo/11/675 has banned the use of pre-ticked check boxes and other 'opt out' selections like these. Consumers must actively opt in to purchase additional extras.

Inviting disaster

When signing up to the professional networking site LinkedIn, you're asked to provide an email address as well as your email password (which may not even be necessary if you're already logged in to your email). Members are then prompted to invite other people to join their network. Existing members are also prompted to expand their network – when they update their status, for example.

LinkedIn helpfully provides some suggested contacts from the member's email account, and if the member agrees, LinkedIn automatically sends an email inviting the contacts to connect, followed by two reminders.

The biggest, most prominent button on the page is the "add connections" button, which looks like your typical "proceed" or "next" button. What's not clear is that there are more suggested contacts than those just shown on the screen, and includes everyone in your email account.

"This is most certainly a 'friend spam' dark pattern," says Brignull. "Some members will take the action in the belief they're doing one thing – setting up their LinkedIn account – when in fact they are doing another – inviting everyone they've ever emailed to become a LinkedIn contact, which can entail lots of unexpected emails being sent in the member's name."

The repercussions range from annoying and embarrassing for most people to professionally and personally devastating for some, and a class action against LinkedIn has been launched in the US of behalf of people affected by this. LinkedIn denies the plaintiff's claim that email addresses had been 'hacked', and says people give their permission to obtain contact email details. Given it's such a common problem, however, the process is not as transparent as it could be.

Big green buttons: recommended!

We particularly love this example of the "disguised ads" dark pattern. A confusing mess of ads and content means you're more likely to click on an ad than the actual button to download the software you want. Those big friendly green buttons mean business.

The dark patterns don't stop there. When downloading software you're usually given a couple of choices: typical wording might be "express installation – recommended" and "custom installation". Less tech-savvy people will most likely choose the express installation, helpfully pre-selected, along with the key word "recommended" – and recommended is good, right? Who would recommend you do something dumb?

Then there are the big, friendly green buttons begging to be pressed. You happily speed through the installation steps with barely a pause to read what you're agreeing to, confident the vendor only has your best interests at heart.

Not long afterwards you may notice you have intrusive new toolbars, a default search engine you've never heard of, icons for additional programs you don't want, potentially malware and spyware – in a word, crapware. Even reputable programs such as Adobe's Reader and Flash, Oracle's Java, and Microsoft's Internet Explorer may slip in all manner of stuff you don't want and make changes to your computer.

So if you've ever wondered how all this stuff got on board, you may have agreed to take it without realising. And that's thanks to the dark patterns that seemed as though they were helping you out.

Ad search

Remember how a few years ago, when searching on Google, you'd see the ads at the top of the page with a yellow background? And have you noticed over time that yellow background getting lighter and lighter? In 2013, the US Federal Trade Commission took a dim view of this dimming hue, and ordered Google (and all search engines) to make ad content clearer, by means of prominent shading and borders and clear text labels that appear before or to the left of the ad.

But with billions of dollars of advertising revenue at stake, should Google be worried? Probably not. When Google bowed to consumer advocates' demands to change the wording from "sponsored link" to "ad", click-throughs actually went up!

How did 'dark patterns' originate?

Dr Harry Brignull, a website user experience design consultant with a PhD in cognitive science, is the man who first coined the term "dark patterns".

"One Friday night a few years ago I was pickpocketed on the way home from a bar. The way they did it was really clever – right in front of my face. When I got home I spent hours on the web reading about all the techniques that pickpockets use.

"I found out they'd used what's called the 'drunk dancer' technique on me, which basically involves the thief pretending to be drunk, hooking onto you and putting pressure somewhere on your body to distract you from what they were doing in your pocket.

"As I read about this, I realised that if I'd known the name of this technique beforehand, I'd never have let it happen. Scams don't work if the victim knows in advance how the scam works.

"Around that time, I was invited to give a presentation at a design industry conference about some of the tricks that low-cost airlines often use to get you to buy insurance or other add-ons. In doing the research, I realised these tricks were far more widespread than I expected.

"I got the feeling that everyone in the design industry sort of knew these tricks existed, but nobody had ever taken the trouble to identify and document them properly. This is where the term 'dark patterns' was born. I wanted to pin a name on them and get people talking about them more."

Fight the dark patterns

  • Ban the pre-ticked box. CHOICE wants to see an end of pre-checked boxes for extra products, services, subscriptions and so on that force you to opt out – similar to the ban in the EU.
  • Know your enemy and familiarise yourself with all the dark patterns out there – you can visit darkpatterns.org to check out the full range.
  • Eternal vigilance – watch out for pre-selected options.
  • Caveat emptor – always read the fine print.
  • Do something, don't just sit back and take it. If a dark pattern has cost you money, try to get a refund – call the department of fair trading or consumer affairs in your state to find out what your rights are.
  • Contact the dark pattern perpetrators. If you feel their tactics are deceitful or misleading, tell them – by phone or email, or on their social media accounts, where others can benefit from the warning. Some companies have changed their sites in response to consumer complaints.
  • Alert others. Submit your example to darkpatterns.org. And let us know, too – have your say in the comments section.

And finally, beware the drunk dancer!