Web Of Trust indicators will only appear if you've got the relevant extension installed and enabled in your browser. Since you've not told us which browser you're using it's hard to give specific instructions but basically you need to check the list of extensions to see if Web of Trust is there and enabled. If it's not then, obviously, you need to reinstall it. If it's shown as there and active (but it's not actually working) then first try simply restarting your browser. If that doesn't work, uninstall the extension and then reinstall it.