Business

The Cost of Mobile Ads on 50 News Websites

By GREGOR AISCH, WILSON ANDREWS and JOSH KELLER

Ad blockers, which Apple first allowed on the iPhone in September, promise to conserve data and make websites load faster. But how much of your mobile data comes from advertising? We measured the mix of advertising and editorial on the mobile home pages of the top 50 news websites – including ours – and found that more than half of all data came from ads and other content filtered by ad blockers. Not all of the news websites were equal. Related Article

to load advertising content
to load editorial content

The amount of data each website uses can vary. To get these figures, we loaded each home page on an iPhone 6 at least five times over two days and repeated the test with an ad blocker enabled.

The difference was easy to spot: many websites loaded faster and felt easier to use. Data is also expensive. We estimated that on an average American cell data plan, each megabyte downloaded over a cell network costs about a penny. Visiting the home page of Boston.com every day for a month would cost the equivalent of about $9.50 in data usage just for the ads.

Here are all the files that made up the Boston.com data during one visit, including one large video ad and many script files used by ad networks. With an ad blocker, those files were gone.
Without ad blocker
With ad blocker
The Los Angeles Times showed smaller ads but included large scripts used by ad networks.
Without ad blocker
With ad blocker
The Guardian was one of the fastest performers in the sample. Ad blockers had a much smaller effect on load times.
Without ad blocker
With ad blocker

Of course, news websites are supported by online ads, and if enough people block the ads the sites may struggle. Ad blockers can also have technical downsides, sometimes causing websites to load erratically. In one of our tests, one website crashed repeatedly when an ad blocker was turned on.

Note: Data is averaged from 10 visits to each website's home page on an iPhone 6 over two days. Estimates for load times assume favorable network conditions and may be understated. The data does not account for text compression, which reduces the size of text files.

Sources: New York Times analysis; Pew Research Center and comScore (top 50 news websites)

Correction: Oct. 1, 2015

An earlier version of a chart with this article breaking down the content on The Guardian’s website based on which has ad blockers and which does not mislabeled some editorial content as advertising.