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 "Guy, Robot", Stewie says that he's the only one who gets social media. A cutaway then showed 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.