Facebook on Wednesday offered a glimpse into how it ranks and shows content in its News Feed, part of an effort to provide more transparency about its operations. The disclosures come in the wake of a May news report alleging liberal political bias in a Facebook feature called Trending Topics.

"News Feed is a system that’s designed and built by people, but people have values and those values are reflected in how we make decisions on a regular basis," Adam Mosseri, vice president of product management for News Feed, told a press briefing.

Mosseri said the core principle of News Feed - the place most people see postings on Facebook - is that posts from family and friends get ranked first. That is followed by "informative" content, which can range from news articles to recipes and is determined by what types of posts an individual tends to click on.

"Entertaining" content is the third priority, and is similarly based on past preferences.

Facebook launched News Feed in 2006 as a way to help users see the content that would be most important to them from their friends, family and pages they choose to follow. It uses an algorithm that it says it is constantly updating, along with human editors, to decide what content it should show customers.

Facebook stressed in a blog post Wednesday that it does not favor certain sources or ideas. "We are not in the business of picking which issues the world should read about."

The company also said it is working to better identify content that users find authentic and surface it higher in the News Feed, as well as removing more "click bait," which it said users find misleading.