Help is on the way for anyone who has ever been puzzled by Google's choice of ads in their Gmail messages and their search results pages.
Google will display a link labeled "Why these ads" in Gmail and search pages that will explain the reasons they were chosen for display.
Some of the elements that may come into play are the user's language, geographic location and recent search queries, Google said on Tuesday in a blog post.
Google will also make it possible for people who are signed into their Google Account to block ads from specific marketers and turn off ad personalization altogether, the company said.
The new tools and functionality will debut at different points in Google search and Gmail over the coming weeks, according to Google.
"We're always working to deliver the perfect ad, and we know that it's important to have a choice about the kinds of ads that are shown to you. If you don't wish to see personalized ads, the choice is yours," wrote Susan Wojcicki, Google's senior vice president of advertising.
Google already provides similar tools and functionality for ads that appear on YouTube and on external websites that carry Google ads via the company's AdSense ad distribution program.
The issue of targeting ads to people based on their online activities is a sensitive one that has drawn attention from privacy watchdogs and the government.
Among the concerns is that people often get tracked and profiled in stealthy ways that they aren't aware of and that they have little or no control over.
This commonly happens through the silent insertion of cookies as people visit websites. These cookies often collect browsing history information so that ads can be personalized.
Legislators and regulators in the U.S. and abroad are taking a hard look at this issue and pondering the establishment of rules. Online ad providers generally argue that government intervention isn't necessary because the industry can monitor its own practices and agree on guidelines.
Tuesday's announcement by Google is aimed at giving people more information about ad targeting and more control over it.