I once used it (on a personal project) to add a sad-face emoji to the page’s <title> if the page wasn’t visible. It would change to a heart when they returned.

I once used it (on a personal project) to add a sad-face emoji to the page’s <title> if the page wasn’t visible. It would change to a heart when they returned. (Edit: since the emoji was prefixed, you could see it on the background tab)