After using #Mastodon for a little bit now, I decided to actually press the mysterious "Bookmark" button to see what it did. I was nervous, hovering the pointer over it for a moment, feeling my heart beating faster, and then.. "click". I did it! ... Suddenly... a portal opened up in front of me. These weird alien chicken like creatures came out of it, which then jumped out of the window, and the portal disappeared. Everything was silent again. I still don't know what that button is actually for.