That statistic, which users will see on Pages below the total number of “Likes,” will be one of four tracked by Pages Insights. The idea is that users will understand a Page with a high People Talking About rating is one that has compelling content. Likewise, content creators will be motivated to make their Pages more comment-worthy.
People Talking About (that might not be the final name for the metric; at press time, Facebook wasn’t sure) will measure user-initiated activity related to a Page, including posting to a Page’s Wall, “liking,” commenting, sharing a Page post or content on the Page, answering a Question posed to fans, mentioning a Page, “liking” or sharing a deal or checking in at your Place.
Read more at Mashable