Facebook is a social networking service and website launched in February 2004 that is used worldwide with millions of users.
In "And I'm Joyce Kinney", Lois states she thought she and Joyce Kinney were good friends that communicate poorly through Facebook. It flashed the screen to a picture of Lois Griffin's Facebook profile stating her Aunt Clara had passed away and was sorry for what she had to go through with cancer. Moments later we see Joyce Kinney "Liking" the comment Lois had made.
In "Back to the Pilot", Stewie worried that interference in the past may alter the timeline so that Cookie Monster invented Facebook and named it Cookiebook.
In "Guy, Robot", Stewie says that he's the only one who gets social media. A cutaway then shows Lois scrolling through posts on her Facebook account, that she was expecting to get likes, but none of them made sense. She then liked one of her own posts, believing that it would "get people started" on liking her post.
In "Petey IV", Brian gets caught by Martha in the act of masturbating to a Facebook photo of her and her mother at her grandfather's funeral and then storms away during the musical number named after her.
Peter regrets checking in at an adult bookstore on Facebook for a 5% discount when Meg likes the post in "Heart Burn".
After a fight with Lois in "Undergrounded", Peter tells Brian that she is pretending nothing has happened on Facebook so she can still post pictures of food. When he complains about being made to sleep outside, she deletes his post.
While being trapped in detention by Principal Shepherd in their own basement in "Movin’ In (Principal Shepherd’s Song)", Peter says he feels reenergized like the time his high school crush Karen Altman friend requested him on Facebook. A cutaway gag then shows Peter gladly accepting her friend request, but it turns out Joe is impersonating the woman and flirting with Peter in disguise as a prank. In payback, Joe himself receives a friend request from a high school classmate of his own named Beatrice Fuller which he accepts, only for it to be revealed that Chris is impersonating this woman. All three of them are shown at their laptops drinking coffee while on Facebook in this cutaway.
In "Single White Dad", all the girls Peter went to high school with have not enjoyed being parents, according to their Facebook status.