Aside from the "/us" link, which only you can go to for obvious reasons, all this does is takes two people and presents the common parts of their timelines. Look at the URL and you see the other person; change it to someone else and it gives the events you have in common with them. After clicking on the link on here and seeing stuff in common with my partner, I tried it with my son and an acquaintance. It's nothing to do with relationship data, and the page is generated on the fly, so it's not like someone's comment on pages of past relationships continuing to lurk as self sustaining entities. So, like, chill.