This module/component/plugin lets you specify a greeting based on the website from which the visitor arrived at your page. It uses the 'referrer' field in the http header. On the admin side, you set up default greeting (if desired) and a greeting for each url you're interested in. On the front side, the greeting can either be displayed in a module or in a content item by means of the plug-in. So, here's the component, the module and the plugin. All are Joomla 1.5 native.