The following tutorial explains how to add/remove help sign to Chameleon Theme top area on a Plone 4 website. For other Plone versions: see instructions for dealing with 'Help' Sign in Plone 3 and Add 'Need Help?' link to Chameleon Diazo Theme in Plone 4.1 tutorial.
There is small area on the top right corner of Chameleon theme reserved for a help sign, but it is not displayed by default.
To make it appear - add document with help shortname into the root of the site (it can contain some helpful and important information for site visitors). The sign will appear and will be linked to that document.
If you again want to remove that sign - delete help document from the site root.