Websites are using hidden tricks to make you click or buy something without __________, and the way they do it can be both baffling and controversial.

Every day, millions of trials are manipulating what you see when you __________ online, to find out how to make you click more links – and spend more money.

Thanks to something called A/B testing, the web __________ you open are not necessarily the same as those shown to another person – they might have slightly different colours, a different headline, etc.

The phenomenon of A/B testing began as a relatively __________ way of improving websites.

What has made it so powerful is that sometimes it throws up results that nobody would have __________ otherwise.

Earlier this year, a Google executive revealed that using a different shade of blue for advertising links on search result pages caused more people to click on those links, which has increased the company’s revenue __________ 200 million.

In recent months, A/B testing has begun to affect the news you read. Some sites test up to 25 headlines to see which performs best. A design consultant Harry Brignull says that these design tricks __________ manipulate users into doing things they wouldn’t otherwise do.

This could be anything from signing up to subscription services to agreeing that their personal data can be shared with third __________.

A lot of these tricks are based on things like confusingly worded forms during sign-up procedures, which appear harmless but in fact sign __________ your privacy in a single click.

However, in the 20th Century, fears grew over the manipulative effects of advertising, leading to __________ of the industry. Perhaps such oversight will face A/B testers in the future.