Facebook already lets you post on someone's timeline or send a message to show your gratitude, but that won't always be... you know, heartfelt enough. What if you want to go the extra mile? That's where the social network's new Say Thanks feature might come in handy. Think of it as Google+ Stories for "thank you" cards. All you do is choose the photos and posts that best represent your time together, and wrap them in a theme; after that, Facebook will automatically generate a video (with a personalized message) that you can share. If you've been meaning to tell a long-term pal just how much you care, you can try Say Thanks today on either the desktop or one of Facebook's mobile apps.