Facebook's appeal to nostalgia tip

Facebook's mission is to, “Give people the power to build community and bring the world closer together.” They've recently rolled out different statistical features that highlight this mission. For example, someone scrolling through their News Feed might come across a box that says: “You've added X friends during the month of February!” 

Facebook taps into individuals' appreciation for human connection and nostalgia. In this example, a user recently shared a memory.  Facebook took that and placed a cute and sweet message in their News Feed pointing out where they can get more of the same any day of the year.

Why this is really good UX:

• Placing this message in the News Feed and not as a notification gets users' eyes on it, whereas they might have ignored a notification from Facebook.
• The copy is short and sweet, and offers value that the user has already proven they enjoy. If someone enjoyed seeing a certain memory before so much, they might want to open the link in the message to see what happened years before.