Facebook changes could mean less time spent on site; shares fall

…News feed to prioritize friends and family posts, not brands
…CEO Zuckerberg says users may spend less time on the site

Facebook Inc. said it’s making major changes to its flagship social network, shifting users’ news feeds back toward posts from friends and family and away from businesses and media outlets — a transition that is likely to mean people spend less time on the site. The shares tumbled the most in more than a year, Bloomberg reports.