Google, working with researchers from the University of California, Berkeley, conducted a study that found 5 percent of users visiting Google sites were infected with Ad Injectors.
An Ad Injector is a type of adware that can put ads into pages you are viewing, replace existing ads with other ads, and block content you are trying to view. As a result of these annoying pop-ups, Google claimed it has received over 100,000 complaints from users of Google Chrome since the start of 2015.
Google said that this type of software brings a variety of problems for users, advertisers and publishers alike. The user side of the problem is easy to see, as most of us have experienced annoying ads that cover up content and seem to get in the way of our web browsing activities.
For publishers and advertisers, this type of malicious software is an even greater problem. Ad Injectors covering up content and bothering users can drive people away. Because most websites make their living off of advertising, this can drive profits down and cost sites a great deal of money.