The issue, and the reason Google was facing a lawsuit, is pretty well-known at this point. From August 2011 through February 2012, Google bypassed the iPhone's privacy settings and collected data on individual users through tracking cookies. Called the "Safari Workaround," it allows Google to collect private information such as gender, race, physical and mental health, shopping habits, social class, location and more. The company then separated people into categories and used this data in the aggregate to provide more targeted and relevant advertising.
Google is likely relieved to close the chapter on this saga, which is over six years old. The company has accused Richard Lloyd, the leader of the suing group, of trying to punish the company instead of actually seeking justice for UK iPhone users. The company has already paid a $22.5 million fine to the FTC in the US over the Safari workaround.
Mr Justice Warby, who heard the case and decided to block the legal action, took this action because there wasn't enough evidence of damage to the affected group, according to the BBC. Additionally, there is no way to figure out how many people were actually affected by the Safari Workaround.
Update, 10/8/18, 1:00 PM ET: This article was corrected to reflect the amount of damages the plaintiffs were seeking from Google.