We've started adding these selectively to internal tools to supplement more complex tools aimed at depicting progress or trend visualization. It's helped a ton, and goes a long way toward turning indecipherable IT goon geek speak into something normal users find helpful (along the same lines as somethings like Google's App Status Dashboard (http://www.google.com/appsstatus), the Stashboard (http://www.stashboard.org/), or the Salesforce.com status board (http://trust.salesforce.com/trust/status/) do for red/yellow/green statuses at a glance.