Once the Internet promised transparent prices and comparisons. But whoever still thinks this is wrong. In fact, thanks to the World Wide Web, a flight, hotel or package holiday can be booked in just a few minutes. And also that there are sometimes incredible bargains.

However, vendors can now respond to demand and supply in an instant - that is, prices can go down and up. An analysis by the Verbraucherzentrale Brandenburg last fall showed that 37 percent of the online retailers examined their prices changed - with price differences up to 100 percent.

The real advantage for hotels, airlines and other providers, however, is the amount of personal data that users voluntarily provide each day. In a split second, a travel portal knows if anyone is surfing from their computer, laptop or smartphone. Whether this user is traveling with the latest iPhone or an Android phone. This indicates the purchasing power of the potential customer.

And not only that IP address and geo data of the person concerned reveal where he lives, where he is currently located, which websites he prefers, what interests he has, and thus allow a precise person profile to adjust the price accordingly.

With ski weather, the ski pass is cheaper

Dynamic pricing is the name given to this type of flexible pricing, and it has long been a routine in the holiday business. For the main and off-season, trade fair surcharges and seasonal price fluctuations have been common there for generations.

Only sophisticated algorithms and Artificial Intelligence now allow even more sophisticated pricing for the purpose of yield optimization. For example, the Swiss Andermatt has been calculating its skipass fares since last year not only according to the day of the week and advance booking period, but also according to the current weather.

The worrying thing about Dynamic Pricing is that when you look for a specific flight, the price changes at each new session, usually upwards. The booking portal thus simulates an increased demand and puts the customer under pressure. Hotel portals reach a similar pressure with the information "Only a few rooms available".

"With this kind of pricing the feelings of the people are manipulated," says Naomi Hodges, security expert of the VPN provider Surfshark, the industry service Eturbonews. That's why software makers not only employ programmers, but also behavioral economists who know exactly how to entice consumers to buy interactively.

The simplest way to prevent a hotel, travel or flight platform from knowing that one and the same person is searching for a travel offer is to leave as few digital lanes as possible in the network .

Even though the EU Parliament has recently approved a regulation requiring online providers of all stripes to inform about personalized prices, implementation will take some time. First, the EU Council still has to endorse the new directive, and then EU members have two years to introduce the new measure.

To avoid digital traces, consumers can pay attention to this:

  • Until then, you should always delete the browser history and above all cookies and regularly empty the cache . If you are still surfing on another browser, you should make sure that it also does not store cookies - these are the small text programs that identify every user on a site.
  • In order to surf without cookies , users of the browser Chrome must activate the "Incognito Mode", which with Safari select the "Private Mode" and with Firefox the option "Private Window".
  • In addition, every user should check travel offers on different devices . Quite often the prices differ between PC, tablet and mobile phone.
  • In addition , users do not log in on the website . For once logged in, the search history can be tracked exactly and inform about preferences that allow the algorithm to optimize the price in favor of the provider. The best way to register as late as possible, so just before the click to checkout. Often you can also register only once as a guest.
  • The most efficient way to prevent personalized pricing is to use a VPN service . Because a VPN (Virtual Private Network) encrypts the Internet connection, and the IP address can be hidden or changed. Curious people then no longer have a chance to spy on searching customers.