Facebook Inc. has begun letting marketers target consumers based on information from some web sites and apps its users interact with.

That builds on the targeted marketing that is based on what consumers share on the social network, such as the pages a consumer Likes, that the social network has long offered to advertisers.

“Let’s say that you’re thinking about buying a new TV, and you start researching TVs on the web and in mobile apps,” Facebook writes in a blog post. “We may show you ads for deals on a TV to help you get the best price or other brands to consider. And because we think you’re interested in electronics, we may show you ads for other electronics in the future, like speakers or a game console to go with your new TV.”

The move will lead to more relevant ads, Facebook says.

The announcement came the same day Facebook announced at the Internet Retailer Conference & Exhibition that it plans to launch a new ad unit, Multiproduct ads, tailored to e-retailers that lets them highlight several products at once in a single ad that appears in the news feed.

The social network also launched ad preferences, a tool that lets users see the information it gathers about them, as well as gives them the ability to change, add or delete that information. Consumers can also opt out of Facebook’s targeting using the Digital Advertising opt-out and on mobile devices using the controls in Apple Inc.’s iOS and Google Inc.’s Android operating systems.

The new ad preferences will debut in the United States in the next few weeks and internationally in the next few months.