In the sidebar of some sites, there are links to chatrooms. Underneath the name of each chatroom is a user's name. Beside this is a time.
While the name seems to match the avatar on the left, it's clear this time is not the time of the last message posted unless there's some crazy caching going on, and I can't think of any other useful thing it could be. Similar times also pop up on hover for each other avatar. So what is it?