Today I found a link to winterba.sh on the top bar. Upon clicking the "I love hats" button, I was offered to wear the L'chaim hat. The hat shows up as an overlay on my profile picture. But when viewing my profile after logging off, the hat is no longer shown. So I assume one's hat is visible only to the same logged in user.
Methinks the hats are ugly anyway, but what's the use of wearing it if others can't see it?