SAN FRANCISCO >> Google is going to stop reading your Gmail in search of opportunities to sell ads.

The change announced today will end a practice that Google has embraced since the company introduced Gmail in 2004. The practice has raised concerns among privacy watchdogs and creeped out some users.

To help finance the free service, Google has been scanning through what Gmail users were discussing and then showing ads connected to some of the topics. Someone writing about running, for instance, might see ads for Nike or Asics shoes.

Google still plans to show ads within Gmail. But instead of scanning through email content, the company’s software will rely on other signals to determine which ads are most likely to appeal to each of its 1.2 billion Gmail users.

The Mountain View, California, company said it would stop the ad-driven scanning of Gmail later this year.

Google says it’s changing course so its free Gmail service operates more like the subscription version that it has sold to more than 3 million companies. The paid Gmail doesn’t include ads, so the company has never tried to scan the content of those users’ emails for marketing purposes.

Despite that, Google said some of its business customers incorrectly assumed the company was scanning those accounts as well. By ending all scanning, Google hopes to end the confusion and sell Gmail to even more businesses.

Gmail now ranks as the world’s largest email service, an indication that most people didn’t care about Google’s scanning methods. Both Microsoft and Apple have publicly skewered Google for having the audacity to mine users’ emails for ad sales, but those attacks didn’t undercut Gmail’s popularity.