The latest Word Press release (are they still naming them after jazz musicians?) contains this gem. You've spent ten years typing blog posts into a white box and ignoring everything outside the typing field and suddenly some genius UX types decide you need to be free of these distractions. So they distract you with a popup telling you about distraction-free writing.
Update: Also note that the "tooltip" is out of alignment with the icon it's supposedly pointing to (hat tip ryz).